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TR41.9 Part-68 FAQs Part 68 FAQ 1. ALLOWABLE NON-OPERATIONAL STATES AFTER TYPE A SURGES TR41.9-01-02-017 2. CORDLESS PHONE - On-Hook Impedance ISSUES TR41.9/00-08-038 3. LINE TESTER - 5 Meg DC Resistance ISSUES TR41.9/00-02-006 4. ROLR ISSUES - testing on same digital stations used in different PBX systems TR41.9/00-02-004 5. Facsimile Header Message Requirement TR41.9/99-11-087 6. ROLR ISSUES -testing digital stations TR41.9/00-02-004 7. ROLR ISSUES - digital stations tested through PBX interfaces TR41.9/00-02-004 8. ROLR ISSUES - wireless digital stations and PBX analog trunks TR41.9/00-02-004 9. ROLR ISSUES - criteria for "product family" TR41.9/00-02-004 10. ROLR ISSUES with POWER FAILURE modes TR41.9/99-11-084 11. ROLR ISSUES - wired digital stations and PBX analog trunks TR41.9/00-02-004 12. SURGE PROTECTORS TO GROUND - Rating Issues TR41.9/99-11-063 13. OPS EQUIPMENT TR41.9/98-11-077 14. ALARM DIALERS & line seizure issues TR41.9/99-08-060 15. INTENTIONAL PATHS TO GROUND discussed 16. ALARM DIALERS TR41.9/98-11-077 17. FAILURE CONDITIONS AFTER SURGE STRESSES TR41.9/98-11-077 18. SURGES TYPE B - issues and recommendations TR41.9/98-02-033 , -038, -040 19. HOOK FLASH and OFF HOOK ISSUES TR41.9/98-02-011 20. DIALING WITHOUT NETWORK ADDRESS PURPOSES TR41.9/98-02-011 21. ENCODED ANALOG ATTESTATION FOR ON-PREMISES S/T INTERFACES TR41.9/98-02-005 22. M-LEAD SURGE PROTECTION ISSUES TR41.9/97-05-033 23. PROPER SETTING OF SYNTHESIZED VOICE TR41.9/95-06-020 24. STAND-ALONE SURGE PROTECTORS WITH C.O. CONNECTIONS TR41.9/95-06-021 25. TRANSFERABILITY OF REGISTRATION TR41.9/95-06-023 26. LEAKAGE AND COMPONENTS RATING TR41.9/95-06-022 ------------------------------------------------------------------------ 1. ALLOWABLE NON-OPERATIONAL STATES AFTER TYPE A SURGES TR41.9-01-02-017 BACKGROUND: A manufacturer is requesting TR41.9’s clarification on the permissible states of the EUT after the Type A surges of 68.302(c). The manufacturer wants to incorporate the surge protector as described in the attached specification sheet. This spec sheet states, among other things: "After a Type A surge the equipment can be faulty, provided that the fault mode causes the equipment to be unusable. The high current Type A surges (101160, 200 A and 10/560, 100 A), will cause the TISP4xxxL3BJ to fail short circuit, giving a non-operational equipment pass to Type A surges." (see attached sheet on the TR41.9 web site contribution TR41.9-01-02-017). However the device as described would cause the supplier's EUT to place a short circuit (permanent off-hook) across tip and ring. ISSUES/PROBLEMS/QUESTIONS: 1. Are non-operational states after Type A surges allowed to include a short-circuit across Tip and Ring? 2. How widespread is the misunderstanding of the fail-safe criteria after Type A surges? How can suppliers be made more aware of the requirements? 3. What is a clear definition of acceptable “non-operational states” for the EUT after Type A surges? AFFECTED P68 SECTION(S): 68.302, 68.312(i) RECOMMENDATION: 1. The equipment manufacturer is responsible for compliance of the complete, final assembled equipment . The component as described is not Part 68 compliant, since it allows the final assembled equipment to provide a short across the line, which is an off-hook condition. This violates the requirements of Section 68.312(i). Equipment may not go off-hook permanently due to a fault mode. Section 68.302 allows a failure mode, but the failure mode is applicable only if the fault is readily visible to the user so that the equipment can be disconnected immediately. 2. Suppliers must not misunderstand the term “non-operational”, which does NOT mean “permanent off-hook or short” of the tip and ring interface. Suppliers may consult this site, attend TIA TR41.9 quarterly meetings, obtain TR41.9's contributions, or join TR41.9's mail reflector list. 2. Acceptable non-operational states of the EUT after Type A surges are: permanent on-hook (idle), permanent opening of the tip and ring line. On the other hand, the EUT must be able to continue to go on-hook and off-hook after Type B surges. The equipment in any case is never allowed to be permanently off-hook. DATE OF RECOMMENDATION: 2-21-2001 ------------------------------------------------------------------ 2. CORDLESS PHONE - On-Hook Impedance ISSUES TR41.9/00-08-038 BACKGROUND: A telco investigated a cordless phone with the feature: "Press any key to cancel Find." Pressing the Talk key during a Find signal did cancel Find, but it also caused the phone to go off-hook. The telco claimed this violated 68.312(i). It was said that, stripped to its essence for this issue, 68.312(i) reads: "[T]erminal equipment shall not by design leave the on-hook state . . . for any other purpose than to request service or answer an incoming call . . . ." It was claimed this phone was designed to go off-hook when canceling a Find signal, even absent any indication that a user might want to request service or answer a call. If the phone both cancelled Find and went off-hook during (and only during) incoming ringing, that could have been acceptable, the telco said. The telco explained one possible network harm due to this as follows. When C.O. dial tone resources are already fully allocated, as during an area emergency or during the busy hour, one additional off-hook event can delay the presentation of dial tone to the next customer. This would degrade service to the next customer. This could be serious if the customer needed to make an emergency call. It was also stated that the user might not know they had taken the phone off-hook, so their line might be busied out unknowingly at an important time. Although not a network harm issue, this could inconvenience the household, making it difficult to place or receive emergency calls. The telco did not propose to recall any phones, because the predicted incidence of network harm problems was infrequent and numerically small. However, it was requested that the Part 68 FAQ be updated to inform interested parties and improve compliance going forward. ISSUES/PROBLEMS/QUESTIONS: The claimed rule violation was that the Talk key both canceled Find (or Page), and simultaneously took the phone off-hook, when a Find signal was active and it could not be certain the user intended to request service or answer a call. Thus by design the phone went off-hook for a purpose other than requesting service or answering a call. AFFECTED P68 SECTION(S): 68.312(i) RECOMMENDATION: It was recommended that cordless phone suppliers, in future products, prevent the Talk key (or equivalent) from causing a phone to go off-hook while canceling a Find or Page signal, unless there is simultaneous incoming ringing or another credible indication the user may intend to go off-hook. DATE OF RECOMMENDATION: 8-15-2000 ------------------------------------------------------------------ 3. LINE TESTER - 5 Meg DC Resistance ISSUES TR41.9/00-02-006 BACKGROUND: A manufacturer has a circuit that is to be connected in series with FCC-registered equipment. The circuit has a momentary manual switch that, when depressed, will allow the testing of the different conditions on the phone line. When the switch is not depressed, the unit passed all applicable tests of Part 68 , including surge type B, etc. When the switch is depressed and held on for the Part 68 test to be run (it is a momentary switch, therefore, the switch is normally open), the resistance presented to the line is less than 5 meg, thus Section 68.312(b)(1) criteria is not met. The switch is intended to be depressed when the unit is installed or when the line is being tested, however, a person would have to press the switch to do this. ISSUES/PROBLEMS/QUESTIONS: 1. Can this device be submitted for certification under Part 68 as a line tester, with instructions in the user's manual to warn the user of the non-compliance state? What are the harms presented to the network? 2. What are the options to certify this equipment, if the response to issue 1 is negative? AFFECTED P68 SECTION(S): 68.312(b)(1) RECOMMENDATION: 1. The product is similar to a sophisticated punch-down block (but with modular connectors) that allows for connection of the telephone lines to separately FCC registered equipment (such as telephone sets) via inside wiring. It was made clear that this equipment’s primary function was not a line tester but a distribution module. As part of the product’s secondary functions, a mechanical, momentary, switch marked “test” is provided and when the switch is depressed, it allows the testing of different conditions on the phone lines. However, when the switch is depressed, the equipment presented a low resistance (much less than the required 5 Meg Ohms) that does not comply with Section 68.312 (b) (1). The main concern was that when the switch is depressed and the resistance presented to the line is less than 5 Meg Ohms, the CO equipment will detect this low current which corresponds to neither a true off-hook nor true on-hook state and this will prevent the carriers from conducting normal, usual line tests. The carriers mentioned that the CO line tests might be performed at any time of the day, not just in the middle of the night. The carriers maintained that this prevention of carriers’ performance of line testing is interfering with CO test functions. The consensus was that the equipment may only be registered with a Z ringer, or the manufacturer may choose to submit a waiver request to the FCC. 2. Some of the recommended options are: The device may be registered as a Type Z ringer which is a conditional registration; this comes with its own limitations (requires telco's assent to connect). The manufacturer may at his own option submit a waiver request to the FCC. The manufacturer could also redesign to bring the equipment into compliance in all states. DATE OF RECOMMENDATION: 2-22-2000 ------------------------------------------------------------------ 4. ROLR ISSUES - testing on same digital stations used in different PBX systems TR41.9/00-02-004 BACKGROUND: A manufacturer has a PBX that provides analog interfaces (i.e. loop start) as well as digital interfaces (i.e. T1 1.544 Mbps). The PBX provides wired proprietary digital station sets and wireless digital handsets. The station sets must meet the Volume Control (VC) ROLR requirements starting on January 2000. ISSUES/PROBLEMS/QUESTIONS: 1. If several PBXs manufactured by the same company are using the same digital proprietary station sets, would it be sufficient to only test the digital proprietary station sets with one representative system and apply the test results across the entire product line? AFFECTED P68 SECTION(S): 68.317 RECOMMENDATION: 1. No. The test data can only be representative if the PBX systems are of a product family, using the same interface trunks and the same loss plan and the same digital proprietary telephone station interfaces. DATE OF RECOMMENDATION: 11-9-1999 ------------------------------------------------------------------ 5. Facsimile Header Message Requirement TR41.9/99-11-087 BACKGROUND: In 1995 (CC Docket 92-90), the FCC issued rules requiring that FAX machines identify the sender of all messages, implementing provisions in the Telephone Consumer Protection Act of 1991. The intent was to control telemarketing cold calls and commercial nuisances such as automatic message dialers and junk FAX mail. These rules first appeared as section 68.318(c)(3), later moved to section 68.318(d): “Telephone facsimile machines; Identification of the sender of the message. It shall be unlawful for any person within the United States to use a computer or other electronic device to send any message via a telephone facsimile machine unless such message clearly contains, in a margin at the top or bottom of each transmitted page or on the first page of the transmission, the date and time it is sent and an identification of the business, other entity, or individual sending the message and the telephone number of the sending machine or of such business, other entity, or individual. Telephone facsimile machines manufactured on and after December 20, 1992, must clearly mark such identifying information on each transmitted message.” Manufacturers of FAX machines seeking Part 68 certification are also required to include a statement in their customer instructions that describes this requirement and tells the user how to set up the FAX header (this is sometimes also called “FAX branding”). A sample of this statement is required in Exhibit J of the application for certification (see chapter in the “Part 68 Application Guide” on “Customer Information”). In April 1997, responding to requests from MCI, Sprint, and Ameritech (see FCC document 97-117 or TR41.9/97-05-051), the FCC clarified situations where the originator and the transmitter of a FAX may be different entities or individuals, specifically with regard to broadcast services. The FCC defined “sender” as the creator of the FAX message’s content, not the service who sends it. Consequently, each FAX must identify the business, entity, or individual who created the FAX rather than the entity who transmits the message. In cases where the message originator and sender agree to both be identified on the FAX, it must be clear which is responsible for the message content and which is merely the message transmitter. ISSUES/PROBLEMS/QUESTIONS: A recent query from a FAX machine manufacturer asked: “… then it seems that the responsibility for conformity is on the user, so long as we take the appropriate measures to assure that they can comply and know what they are doing. Do you agree with this?” AFFECTED P68 SECTION(S): 68.318(d), “Telephone facsimile machines; Identification of the sender of the message” RECOMMENDATION: The questioner is correct, but to clarify so there is no misunderstanding, FAX machine manufacturers are required to: 1) Provide a means to insert the FAX header in every FAX transmission. 2) Follow the instructions for customer information in the “Part 68 Application Guide,” specifically: a) Advise the customer about the requirement and the need to always use the FAX header when sending a FAX (specific language in the Guide). b) Provide clear and simple instructions to the customer telling how to enter the required information in the FAX header. c) Include a copy of these customer instructions in Appendix J of the application for certification. 3) Manufacturers are further advised to put the header set-up instructions in an easily accessible location and to make this process easy, making it easy for their customers to comply with this requirement. DATE OF RECOMMENDATION: 11-9-1999 ------------------------------------------------------------------ 6. ROLR ISSUES -testing digital stations TR41.9/00-02-004 BACKGROUND: A manufacturer has a PBX that provides analog interfaces (i.e. loop start) as well as digital interfaces (i.e. T1 1.544 Mbps). The PBX provides wired proprietary digital station sets and wireless digital handsets. The station sets must meet the Volume Control (VC) ROLR requirements starting on January 2000. ISSUES/PROBLEMS/QUESTIONS: 1. Are the station sets required to be tested for the VC ROLR requirements by themselves? AFFECTED P68 SECTION(S): 68.317 RECOMMENDATION: If the station sets are digital and proprietary and cannot be used by themselves without the system, they must be tested with the system DATE OF RECOMMENDATION: 11-9-1999 ------------------------------------------------------------------ 7. ROLR ISSUES - digital stations tested through PBX interfaces TR41.9/00-02-004 BACKGROUND: A manufacturer has a PBX that provides analog interfaces (i.e. loop start) as well as digital interfaces (i.e. T1 1.544 Mbps). The PBX provides wired proprietary digital station sets and wireless digital handsets. The station sets must meet the Volume Control (VC) ROLR requirements starting on January 2000. ISSUES/PROBLEMS/QUESTIONS: 1. Through what interface of the PBX must the digital station sets be tested for VC ROLR? Analog (i.e. loop start) or Digital (i.e. T1) or both? 2. Should the PBX and the station set be considered as one big Black Box Telephone for the purposes of VC ROLR testing? AFFECTED P68 SECTION(S): 68.317 RECOMMENDATION: 1. Both. The PBX loss plan plays an important role in the test for the reason that when the station set was tested through an analog interface of the PBX, the network perceives the complete entity as one black box analog giant phone; when the station set was tested through a digital interface of the PBX, the network perceives the complete entity as one black box digital giant phone. Thus, different loss compensations will be applied by the system. Therefore in order to verify the appropriate loss compensation, the digital station should be tested through both the analog and digital interfaces of the PBX, unless the PBX does not provide both types of interfaces 2. Yes, as indicated above. DATE OF RECOMMENDATION: 11-9-1999 ------------------------------------------------------------------ 8. ROLR ISSUES - wireless digital stations and PBX analog trunks TR41.9/00-02-004 BACKGROUND: A manufacturer has a PBX that provides analog interfaces (i.e. loop start) as well as digital interfaces (i.e. T1 1.544 Mbps). The PBX provides wired proprietary digital station sets and wireless digital handsets. The station sets must meet the Volume Control (VC) ROLR requirements starting on January 2000. ISSUES/PROBLEMS/QUESTIONS: 1. If the PBX only provides an analog interface, must the wireless station meet the ROLR in all 3 loop lengths, as specified? Should the air link matter? AFFECTED P68 SECTION(S): 68.317 RECOMMENDATION: 1. Through the analog interface of the PBX, the wireless digital station set should still be tested for all 3 specified loop lengths. This also applies to cordless phones (cordless handset working in conjunction with a base station connected to the network via a regular wireline loop start line) which must compensate for the losses over the different loop lengths. DATE OF RECOMMENDATION: 11-9-1999 ------------------------------------------------------------------ 9. ROLR ISSUES - criteria for "product family" TR41.9/00-02-004 BACKGROUND: A manufacturer has a PBX that provides analog interfaces (i.e. loop start) as well as digital interfaces (i.e. T1 1.544 Mbps). The PBX provides wired proprietary digital station sets and wireless digital handsets. The station sets must meet the Volume Control (VC) ROLR requirements starting on January 2000. ISSUES/PROBLEMS/QUESTIONS: 1. How should product lines be differentiated for the purpose of ROLR testing ? By family designation? By FCC Registration designation? AFFECTED P68 SECTION(S): 68.317 RECOMMENDATION: 1. Examples of a product family include systems that differ only in capacity (i.e, 4x8, 6x12 systems, where the "bigger brother" differ only in the fact that it can accommodate more capacity). Station sets must be tested for each PBX that is different (not part of the family) as the PBX loss plan, and its interface trunks as well as station interfaces do have an effect on the same digital proprietary station sets. A Product family should be differentiated by the above criteria rather than by FCC Registration Number, as sometimes, a "big brother" system that has received the same FCC Registration Number may incorporate additional interface trunks, etc. than the "little brother" system covered under the same FCC Number. The key issue in compliance is whether the test data obtained for compliance is representative enough. When in doubt, ensure that each station set complies. DATE OF RECOMMENDATION: 11-9-1999 ------------------------------------------------------------------ 10. ROLR ISSUES with POWER FAILURE modes TR41.9/99-11-084 BACKGROUND: Many multifunction corded telephones that use AC-powered power adaptors now on the market will continue to function as a standard telephone after loss of AC power to the adaptor, but will loose many of their functions such as LCD display, speaker-phone, and Volume Control. ISSUES/PROBLEMS/QUESTIONS: 1. Is it required to provide the Volume Control feature in the event of a power failure? (Note: Industry Canada CS-03 exempts compliance with the Volume Control in the case of AC power failure) AFFECTED P68 SECTION(S): 68.317 RECOMMENDATION: The receive gain requirements apply to telephone sets that are fully operational. They do not apply during AC power failure, if a telephone set is designed to operate with AC-adapter powering. DATE OF RECOMMENDATION: 11-9-1999 ------------------------------------------------------------------ 11. ROLR ISSUES - wired digital stations and PBX analog trunks TR41.9/00-02-004 BACKGROUND: A manufacturer has a PBX that provides analog interfaces (i.e. loop start) as well as digital interfaces (i.e. T1 1.544 Mbps). The PBX provides wired proprietary digital station sets and wireless digital handsets. The station sets must meet the Volume Control (VC) ROLR requirements starting on January 2000. ISSUES/PROBLEMS/QUESTIONS: 1. If the PBX only provides an analog interface, must the wired digital station meet the ROLR in all 3 loop lengths, as specified? AFFECTED P68 SECTION(S): 68.317 RECOMMENDATION: 1. Through the analog interface of the PBX, the wired digital proprietary station set must be tested for all 3 loop lengths, the reason being that when the station set is tested through an analog interface of the PBX, the network perceives the complete entity as one black box analog giant phone; when the station set is tested through a digital interface of the PBX, the network perceives the complete entity as one black box digital giant phone. Thus, different loss compensations will be applied by the system. DATE OF RECOMMENDATION: 11-9-1999 ------------------------------------------------------------------ 12. SURGE PROTECTORS TO GROUND - Rating Issues TR41.9/99-11-063 BACKGROUND: The product is a channel bank FXO board containing multiple identical interfaces that are software-selectable to be either loop start or ground start interfaces. In the ground start mode, a ring-to-ground solid state relay circuit is activated by software. In the loop start mode, the circuit is functionally disabled but the circuit hardware is still present. The solid state relay in the circuit has a breakdown rating of less than 1000 V. This caused the interface (in the loop start mode) to fail the leakage current limitations requirements of Section 68.304 [in the ground start mode, the interface is exempt from the tests of Section 68.304 and does meet the ground current capabilities requirements of Section 68.306(e)(1)]. ISSUES/PROBLEMS/QUESTIONS: The interface incorporates surge protectors to ground which normally would have operated to clamp hazardous voltages to ground before the ring-to-ground solid state relay breaks down, however, Part 68 requires the protectors to be disconnected for the leakage tests, which leaves the solid state circuit unprotected and thereby allowed to reach its breakdown voltage. This situation is seen to be unlikely to happen in real life since the protectors would have operated before the solid state circuit breaks down. The suggestion of a hardware strap was not seen as desirable to the manufacturer as the board incorporates several identical interfaces and the board would have to be removed from the host chassis backplane for straps to be changed, causing the operation of several lines to be disrupted. AFFECTED P68 SECTION(S): 68.304, 68.306(e)(1) RECOMMENDATION: If the interface can prove it has dielectric barriers through other components in the circuit (transformers, relays), in the loop start mode, with the ground connection removed from the ring-to-ground resistor (and with the surge protectors removed from the circuit), then it would be considered compliant with the spirit of Part 68. It was suggested to the manufacturer to submit his Part 68 application to the FCC with test data showing compliance as specified, in both the loop start mode and the ground start mode. DATE OF RECOMMENDATION: 8-18-1999 ------------------------------------------------------------------ 13. OPS EQUIPMENT TR41.9/98-11-077 BACKGROUND: Part 68, Section 68.308(7) gives requirements for OPS equipment. It states that there are different requirements for different classes of OPS equipment. What are the differences in the classes are or and where can one find the definitions for each class of OPS? ISSUES/PROBLEMS/QUESTIONS: 3 Classes of OPS are referenced in 68.308 , A B and C. Form 730 also refers to 3 distinct OPS codes. AFFECTED P68 SECTION(S): 68.308(7) RECOMMENDATION: Off-premise station (OPS) ports of premises communication systems (e.g., private branch exchanges or key telephone systems) provide dc loop supervision network control signaling and talking battery to the remote OPS stations. The difference between each class is dependent on the loop lengths that can be supported by the OPS ports for the connection of remote stations. Figure 68.3 (f) in Part 68, Subpart A, illustrates the various loops supported by the classes of OPS. NOTE: Notwitthstanding the specification of 16 mA in Figure 68.3(f), it was determined in TR41.9 - 2/99 meeting that the DC conditions for OPS Class A, B and C ports requirements are stated in FCC 68.308(b)(7)(ii)(c). The dc current into the OPS line simulator circuit must be at least 20 mA for Class B and C OPS ports although the minimum dc current for the Figured 68.3(f) OPS loop simulator is 16 mA. Testing performed on an OPS port must show compliance with the 20mA as specified in Subpart D, 68.308(b)(7)(ii)(c), where the technical requirements reside. DATE OF RECOMMENDATION: 8-17-1999 ------------------------------------------------------------------ 14. ALARM DIALERS & line seizure issues TR41.9/99-08-060 BACKGROUND: A manufacturer markets an alarm control panel with associated control devices. In the event of an emergency situation, the alarm control panel would seize the line, pulse the line at a rate of 100 pps for 1 second to signal the other control devices that are connected to the telephones on the inside wiring of the house. Upon detecting this pulse signal, each associated control device would disconnect the telephone instrument to which it is connected, thus freeing the telephone line for the alarm control panel to dial out. ISSUES/PROBLEMS/QUESTIONS: The issue is on compliance with 68.312(i) that allows terminal equipment to go off hook only for the purpose of answering an incoming call or originating a call. This alarm control panel would be going off hook for purposes other than those allowed. The problems revolve around the line seizure conditions and characteristics of an alarm control panel. In the past, this type of devices would be wired in the house ahead of all other telephone sets (cc USOC RJ31X) so that in the event of an emergency, the device would disconnect all the other telephones and dial out. In the present environment, often the alarm device is added to the house after several telephones have been wired and connected and there is no easy way to ensure that the alarm control panel will be wired ahead of all other devices. AFFECTED P68 SECTION(S): 68.312(i) RECOMMENDATION: A. if at least one telephone is already off-hook, there is no issue with compliance with 68.312(i) [line already off hook] B. If all associated telephones are on-hook, and the alarm control panel goes off-hook, performs its pulsing sequence and continues to stay off-hook in order to subsequently network address (dial out), then it will comply with 68.312(i). This is the suggested design to the manufacturer of the alarm panel. C. If all associated telephones are on-hook, and the device goes off-hook, performs its pulsing sequence and then goes on hook to wait for the associated instruments to free the line, it would technically violate the requirements of Section 68.312(i). It was mentioned that, however, this device intends to subsequently use the line to dial out, and the efforts to clear the line would be seen by network operators as less "harmful" than if the device were to use the line to open a door phone controller, for example. It was mentioned that the series of pulses from the device may be seen as a 100 Hz signal and the signal is then subject to the signal power requirements of 68.308. If the signal power of the resulting signal complies with the loop start requirement of -9dBm, then the device could be considered as Part 68 compliant (given the emergent circumstances) even though it technically violates the requirements of Section 68.312(i). This solution is not seen as desirable as the one suggested in subparagraph B above. DATE OF RECOMMENDATION: 8-17-1999 ------------------------------------------------------------------ 15. INTENTIONAL PATHS TO GROUND discussed BACKGROUND: Part 68, Section 68.304 allows for intentional operational paths to ground (as in DID, ground start ) to be excluded from the 1000 V leakage test. Leads excluded for this purpose must be subjected to the tests of 68.306 (c)(1) for ground integrity demonstration. A manufacturer has an E1/T1 CSU interface card. In the T1 mode, there is no intentional operational path to ground. However, in the E1 mode, there is a circuit to ground that would cause the device to fail the leakage test. This circuit may or may not affect the transverse balance characteristics of the T1/CSU. ISSUES/PROBLEMS/QUESTIONS: 1. Is the circuit for E1 operation considered an intentional operational path to ground? 2. Should the card have a jumper that would disconnect the circuit to ground in T1 operation? AFFECTED P68 SECTION(S): 68.304 Leakage Current Limitations 68.306(e)(1) intentional operational paths to ground 68.310 Transverse Balance RECOMMENDATION: Since the intentional path to ground is not an inherent function for T1 operation, and E1 functions are not within the purview of FCC Part 68, the exemption for intentional path is not allowed. The terminal equipment must comply with the requirements of Section 68.308. Alternatively, the equipment could be designed to effectively disconnect the path to ground in T1 operation, such as the use of a jumper. DATE OF RECOMMENDATION: 2-18-1999 ------------------------------------------------------------------ 16. ALARM DIALERS TR41.9/98-11-077 BACKGROUND: A manufacturer has a PBX system with a dial out modem, the modem will only dial out if some of the hardware in the system has crashed. The modem will dial out to a paging service to contact a technician. The tech will then take the necessary repair to the PBX system. The autoredial attempts from the modem can be set well beyond the specification of Part 68 Subpart D section 68.318(b). Would this equipment qualify for registration as an alarm dialer? ISSUES/PROBLEMS/QUESTIONS: According to Part 68, emergency dialers are exempt from the limitations placed on automatic redialing functions AFFECTED P68 SECTION(S): 68.318(b) RECOMMENDATION: Yes. Note the statement in the November 1997 Order that Emergency alarm dialers and dialers under external computer control are exempt from these requirements. Note the definition in the Application Guide for equipment code AL implies that Alarm dialing systems fire, intrusion, equipment failure and the like. A internal modem within a terminal equipment, when used in emergency conditions such as the one described qualifies for the exemption under Emergency dialers, even though the terminal equipment primary function is not of an alarm dialer. DATE OF RECOMMENDATION: 11-18-1998 ------------------------------------------------------------------ 17. FAILURE CONDITIONS AFTER SURGE STRESSES TR41.9/98-11-077 BACKGROUND: What constitutes failure for the 68.302 Type A surge test? ISSUES/PROBLEMS/QUESTIONS: Surge stresses are environmental conditioning tests. AFFECTED P68 SECTION(S): 68.302(b)(3) RECOMMENDATION: Since surge stresses are conditioning tests, the Terminal Equipment must undergo all the applicable electrical tests after the surges. Any failure to comply with the criteria of all applicable Sections of Part 68 after the surges constitutes a failure. This determination applies to both Type A and Type B surges. Note: Pursuant to 68.302(b)(3), the Terminal Equipment is allowed to reach some failure modes in violation of the transverse balance requirements of Section 68.310 provided that such failure modes are intentionally designed and that the equipment would become substantially and noticeably unusable by the user, or an indication would be given (e.g. alarm) in order for the equipment to be immediately disconnected from the telephone line. DATE OF RECOMMENDATION: 11-18-1998 ------------------------------------------------------------------ 18. SURGES TYPE B - issues and recommendations TR41.9/98-02-033 , -038, -040 BACKGROUND: The Harmonized Part 68 requires that Surges Type B be performed with the following failure criteria, specified in Section 68.302(c)(3): "RTE shall be capable of withstanding the energy of Surge Type B without causing permanent opening or shorting of the interface circuit and without sustaining damage that will affect compliance with these rules" ISSUES/PROBLEMS/QUESTIONS: 1. Need for better definition of "permanent opening", perhaps relating to a minimum amount of current drawn from the interface. 2. Need for more precise specification of what can happen after the Surges Type B: equipment does not need to transmit, etc. 3. Need for better specification of the tests necessary to be performed after the Surges Type B (i.e., all tests, a subset of tests, etc.) AFFECTED P68 SECTION(S): 68.302(c)(3) failure mode RECOMMENDATION: It is necessary to perform ALL test for those states achievable after application of the Type B surge. This is necessary to ensure that equipment continues to be in compliance with the requirements of Subpart D of Part 68. Often, the very last test to be performed is the one yielding a failure to meet the appropriate criteria. A transverse balance failure for example may not be apparent visually until the equipment is tested according to Section 68.310. The following premise was used as the basis for the recommendation: If ALL the required tests were NOT performed after the Type B surges, equipment that had not undergone this complete testing after the Type B surges may harbor non-compliance parameters that would surface later in subsequent modification filings and would be extremely difficult to trace, specially if different test labs were used. An operational test alone may not cover the effects of the Type B surge stress on the terminal equipment. Based on this potential problem of non-uniformity of test data that could: a. create widespread complaints to the FCC and b. foster difficulties of tracing the problems for the manufacturers and test labs TR41.9 recommends to the FCC Part 68 Review Staff to look for complete applicable test data ( (1) before stresses, (2) after Type B stresses, and (3) after Type A stresses in all Part 68 applications. Regarding the state of the equipment after the Surge Type B, TR41.9 committee agreed that the equipment under test must go on-hook and off-hook (or provide an idle and active state, for interfaces not drawing loop current), but other functionalities (data transmission, DTMF dialing, etc.) are not necessary. Some examples of equipment conditions after Type B stress and their acceptability: OK Equipment continues to go on-hook and off-hook Equipment needed to be reset Cycling of power, whether through commercial power or batteries NOT OK Equipment remains permanently on-hook Equipment remains permanently off-hook Replacing components in interface:e.g. fuses, transformers, relays, etc. Replacing components such as ROM chip in control circuit, or fuse in power supply circuit DATE OF RECOMMENDATION: 2-16-1998 ------------------------------------------------------------------ 19. HOOK FLASH and OFF HOOK ISSUES TR41.9/98-02-011 BACKGROUND: A manufacturer designs a door phone system comprised of a door bell and a relay system that would connect a door speakerphone directly to the house phone. While on the phone with a remote caller, if the owner hears his house doorbell, he would hookflash, then be connected to the visitor at the door speakerphone; the outside line is on hold and would be re-connected after a second hook flash. If the house phone is not being used at the time a visitor rings the bell, the owner can pick up the house phone, hook flash, then be connected to the visitor at the door speakerphone. ISSUES/PROBLEMS/QUESTIONS: Would this device violate the requirements of Section 68.312(i)? 68.312(i) states: "Transitioning to the Off-Hook State. Registered terminal equipment and registered protective circuitry shall not by design leave the on-hook state by operations performed on tip and ring leads for any other purpose than to request service or answer an incoming call, except that terminal equipment that the user places in the off-hook state for the purpose of manually placing telephone numbers in internal memory for subsequent automatic or repertory dialing shall be registerable. Make-busy indications shall be transmitted by the use of make-busy leads only as defined in §§ 68.3 and 68.200(j)." AFFECTED P68 SECTION(S): 68.312(i) RECOMMENDATION: When the user was already off hook in an ongoing conversation, there is no harm generated whereas when the user picked up the phone to answer the doorbell while not requesting network services would be considered as violating 68.312(k). It was mentioned that the FCC has already allowed CPE to go off hook in violation of 68.312(k) for programming purposes, and that the hookflashing situation could be construed as another application of “exceptional uses”. The hookflash area was considered to be a “gray” area, and timing considerations were discussed. In the end, it was concurred that, although the user of a CPE may be the one initiating the action, and that CPE, not users, fall under the jurisdiction of Part 68, CPE should not be designed in such a way that would allow the user to intentionally violate Part 68 rules. Note: The intent of Section 68.312(k) is to prevent PERMANENT shorting of the telephone line. Going off hook and drawing dial tone without a request for network services is a violation of 68.312(k) in the truest sense. However, since the hookflashing lasts basically for a very short period, there should be no network harm generated in the practical sense. DATE OF RECOMMENDATION: 2-16-1998 ------------------------------------------------------------------ 20. DIALING WITHOUT NETWORK ADDRESS PURPOSES TR41.9/98-02-011 BACKGROUND: A manufacturer designs a door phone system comprised of a door bell and a relay system that would connect a door speakerphone directly to the house phone. While on the phone with a remote caller, if the owner hears his house doorbell, he would hookflash, dials a 2-digit number, then be connected to the visitor at the door speakerphone; the outside line is on hold and would be re-connected after a second hook flash. If the house phone is not being used at the time a visitor rings the bell, the owner can pick up the house phone, hook flash, dials a 2-digit number, then be connected to the visitor at the door speakerphone. ISSUES/PROBLEMS/QUESTIONS: Would this device violate the requirements of Section 68.312(i)? 68.312(i) states: "Transitioning to the Off-Hook State. Registered terminal equipment and registered protective circuitry shall not by design leave the on-hook state by operations performed on tip and ring leads for any other purpose than to request service or answer an incoming call, except that terminal equipment that the user places in the off-hook state for the purpose of manually placing telephone numbers in internal memory for subsequent automatic or repertory dialing shall be registerable. Make-busy indications shall be transmitted by the use of make-busy leads only as defined in §§ 68.3 and 68.200(j)." AFFECTED P68 SECTION(S): 68.312(i) RECOMMENDATION: It was unanimously concluded that the case where the door controller was activated by the use of digit dialing, definitively violates 68.312(i). In the end, it was concurred that, although the user of a CPE may be the one initiating the action, and that CPE, not users, fall under the jurisdiction of Part 68, CPE should not be designed in such a way that would allow the user to intentionally violate Part 68 rules. DATE OF RECOMMENDATION: 2-16-1998 ------------------------------------------------------------------ 21. ENCODED ANALOG ATTESTATION FOR ON-PREMISES S/T INTERFACES TR41.9/98-02-005 BACKGROUND: CS-03 Standard allows S/T interfaces that orginates encoded analog signals but remain on-premises to be certified without being tested for signal power; an attestation is required to be submitted to the Industry Canada to provide assurance that the encoded analog content does not exceed the -12 dBm limit. ISSUES/PROBLEMS/QUESTIONS: 1. encoded analog content limitations have been traditionally applied at the point of origination in Part 68. Even though the interface stays on premises, the signals can be carried by an NT1 into the network and be decoded in the network. The NT1, being modular, and can obtain registration on its own, will not be tested for encoded analog signal power as it does not generate these signals. 2. the rationale for the requirements in CS-03 was that it was difficult to obtain test equipment at the time of the adoption of ISDN in CS-03 (circ. 1990). 3. encoded analog testing is required of the same S/T interface if it goes off-premises on common carrier facilities AFFECTED P68 SECTION(S): 68.308(h)(4) encoded analog content, BRI 68.308(h)(2)(v) encoded analog content, 1.544 Mbps (T1 and PRI) RECOMMENDATION: Since testing is applied at the U interface, there is no technical reason to use attestation for analog content in lieu of testing at the S/T interface. The committee agreed to recommend TAPAC to revisit the exemption as stated in CP-01 and to delete this provision. DATE OF RECOMMENDATION: 2-1-1998 ------------------------------------------------------------------ 22. M-LEAD SURGE PROTECTION ISSUES TR41.9/97-05-033 BACKGROUND: The Harmonized Part 68, Section 68.304 allows for protection paths to ground to be separately evaluated under 68.306(e)(2), however, under this section, the protection component must undergo a test voltage of 120V or 300V to ground. M-Lead surge protection to ground on the A side of the interface is normally a zener rated at 60-80VDC. This device would fail the new 68.306(e)(2) requirements. ISSUES/PROBLEMS/QUESTIONS: Specifically exclude M-lead protection paths to ground, in E&M circuits on the A side of the interface? AFFECTED P68 SECTION(S): 68.304 leakage current 68.306(e)(2) intentional protection paths to ground RECOMMENDATION: EUT which have intentional conducting paths to ground and are therefore deferred from High Voltage AC leakage tests contained in CS-03's 2.2.1/FCC's 68.304 shall, if that path is an operational intentional path, require only the ground integrity test of 2.3.9.1/68.306(e)(1). Even if there should also be a protective intentional path to ground in the same network interface, the operational path takes exclusive precedence over the protective, negating the requirement for the I-Leakage test. Only those EUT with protective-only paths to ground shall require the I-Leakage test of 2.3.9.2/68.306(e)(2). DATE OF RECOMMENDATION: 5-1-1997 ------------------------------------------------------------------ 23. PROPER SETTING OF SYNTHESIZED VOICE TR41.9/95-06-020 BACKGROUND: Multi-media devices have the capabilities of an answering machine, i.e. they allow recording from an internal/external source and playback of machine-generated messages. In some cases, the MIC input is located on the host computer that is not included as part of the registration envelope, making this input a non-registered connection. Host software may also allow volume adjustments for recording and/or playback. ISSUES/PROBLEMS/QUESTIONS: Does the card manufacturer have to set the maximum level? AFFECTED P68 SECTION(S): 68.308(b) Voice-band metallic signal power RECOMMENDATION: The card must limit the maximum output to the network to less than the allowed maximum level of its class of service (i.e. less than -9 dBm for loop start, less than -15 dBm for tie trunk, etc.), in the worst case scenario (with the input levels to the card at maximum, etc.). DATE OF RECOMMENDATION: 6-1-1995 ------------------------------------------------------------------ 24. STAND-ALONE SURGE PROTECTORS WITH C.O. CONNECTIONS TR41.9/95-06-021 BACKGROUND: Surge protectors are getting more and more sophisticated. Some are actually power line outlet bars with telephone jacks where front-end secondary protection circuitry is provided for tip and ring inputs. This may include series fusible resistors and parallel varistors. ISSUES/PROBLEMS/QUESTIONS: 1. The varistors may draw enough current to provide a high load on the line during ringing. 2. Potential open circuit of the fusible resistors after the surges (not allowed under Method B of 68.302). 3. Are these devices required to be registered under P68? AFFECTED P68 SECTION(S): 68.312 (b) On hook impedance 68.302 (d) & (e) Metallic and Long. Surges RECOMMENDATION: If these devices are not electrically transparent (i.e with resistors in series and surge suppressors in parallel with tip and ring of the associated registered equipment), they must be P68 registered, due to their potential effect on compliance of the associated registered equipment with the requirements of 68.302 (Method B surges), 68.304 (Leakage), 68.308 (in-band and out-of-band noise), 68.310 (Longitudinal Balance) and 68.312 (on hook impedance). DATE OF RECOMMENDATION: 6-1-1995 ------------------------------------------------------------------ 25. TRANSFERABILITY OF REGISTRATION TR41.9/95-06-023 BACKGROUND: Modem and other PC modules have been registered as OEM devices to be installed in a final assembly. Differences between OEM devices: modem cards vs. modules plugging into a host mother board that provides tip and ring and ground traces to backplane of host systems, etc. ISSUES/PROBLEMS/QUESTIONS: Non-compliance may occur causing longitudinal balance and leakage problems if tip and ring traces are too close to ground through various paths on the host system. Host devices may have other components (such as filter caps) to ground that may cause on-hook impedance problems, etc. Non-compliant network connectors may be provided by the host assembly. AFFECTED P68 SECTION(S): 68.304 Leakage Current Limitations, 68.308 Signal Power Limitations, 68.310 Longitudinal Balance, 68.312 on hook impedance RECOMMENDATION: see Appendix P of the Application Guide for component device guidance. Further work will be done on this issue. DATE OF RECOMMENDATION: 6-1-1995 ------------------------------------------------------------------ 26. LEAKAGE AND COMPONENTS RATING TR41.9/95-06-022 BACKGROUND: A circuit designer wanted to use the same telephone interface coupling transformer, used in a similar device that is P68 registered. When he found out from the transformer manufacturer that the component is rated lower than the P68 required 1000 V, he contacted the FCC to see if he could still use the component. At the same time, he had the component tested at a private lab and the sample tested happened to pass the leakage test of 68.304. He wanted the FCC to allow him to use the component. Component rating of the interface has been required by the FCC as part of Exhibit E of the P68 application to ensure that dielectric components used in the interface are designed to withstand the proper voltage - not just in the sample tested. ISSUES/PROBLEMS/QUESTIONS: How should components be rated and how do these ratings relate to Part 68 requirements? Should the leakage current limit be reduced? AFFECTED P68 SECTION(S): 68.304 dielectric barrier and leakage current limitations RECOMMENDATION: a. If a component in the telephone interface circuit is relied upon for dielectric isolation barrier, then it is recommended that this component be rated at 1000 Vrms. b. There is no recommendation for changing the present maximum allowed leakage current of 10 mA peak. DATE OF RECOMMENDATION: 6-1-1995