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To: Tung, Tailey
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My web searches on EIA-RS-478-1981 and EIA-478 show the following:
1. Two references to NENA Recommended Generic Standards for E9-1-1 PSAP Equipment: One of these references is to an old draft and the other is to the current draft. Mention of 478 is: E9-1-1 TRUNK CONNECTION TO PSAP For nominal speech levels, see EIA RS-478 3.10 1A2 Key Telephone System Interface Systems that are based on 1A2 key technology must comply with EIA RS-478 and EIA RS-487.
2. About four Florida state specifications list RS-478 along with EIA
RS-470, EIA RS-232, EIA RS-464, with the source being Electronic Industries Association at the 2001 Eye Street address. One of these specifications is for an electronic KTS using solid-state control and PCM switching.
3. A 1995 Vermont E911 Board Request For Proposal:
Handsets shall conform to the transmit objective loudness rating specified in the Electronic Industry Association Recommend Standard, EIA RS-478 Multi-Line Key Telephone Systems (KTS) for Voice Band Applications.
4. Postal Computing Environment Handbook AS-820 June 1999:
Un sistema de cableado debe cumplir con las normas y estándares definidos por la ANSI/EIA/TIA indicadas en sus boletines 568, 568A, 569, 570. Así mismo debe soportar los diferentes estándares de la industria como son IEEE 802.5, IEEE 802.3, ANSI X3T9, TP-PMD, EIA-232-D, EIA-422-A, EIA-423-A, EIA 478, EIA-464-1, NTSC, PAL, SECAM,RGB Video, et
6. Avaya SYSTIMAX SCS Application Guide:
The following list of documents is provided to support the listed
applications in this document: EIA-478, Multi-Line Key Telephone Systems (KTS) Voiceband Applications, 1992
7. Bell Atlantic GENERAL SERVICES ADMINISTRATION (GSA) WITS2001:
Non-ISDN telephone sets shall conform to EIA-470 (Telephone Instruments with Loop Signaling for Voice Band Application) or EIA-478 (Multiline Key Telephone Systems [KTS] for Voice Band Application).
8. SYSTIMAX Ò Structured Connectivity Solutions (SCS):
Para pedir os documentos citados para os padrões locais atuais: EIA-478,
9. New Zealand testing authority: Tests - Return loss (EIA RS-478 4.4.9)
Comments on the above:
Do we really want people (see 1) using a standard that has not been updated since 1981 for nominal speech levels? For transmit objective loudness rating (see 3)? Or for return loss (see 9)?
The title of 478 is the only TIA document on KTS. Consequently it finds its way into many reference lists (1, 2, 4, 5, 6, 8)
Do we really want two TIA standards, one up-to-date and the other ancient, that cover some of the same material (see 7)?
The TIA description of EIA-478, Multi-Line Key Telephone Systems (KTS) for Voiceband Application is:
This 100-page document, the third in a series, covers key telephone
equipment. The other two documents are the latest editions of EIA-464 and EIA-470-A. This Standard establishes performance and technical criteria for interfacing and connecting with the various elements of the public telephone network, and will be of value to producers and purchasers of key telephone equipment, and producers of auxiliary equipment intended for use with such systems. Key telephone systems which conform to the new Standard can reasonably be expected to provide quality service in most applications in the U.S. network. Thus, although the document is written around conventional key systems of the familiar "1A2" type, it will be invaluable as a guide to designers of new all-electronic and quasi-electronic key systems as well. Included in EIA-478 are criteria on transmission characteristics, loop supervision and signaling, and alerting signals. This standard was adopted and approved for DoD use on March 9, 1981.
This description certainly makes the standard sound appealing. But, a quick look at 478 shows how obsolete it is:
Loop start access line characteristics have been updated.
Ringing types have been reduced from those listed
Type I and type II dial pulse receivers are specified. Does anyone still use these?
Type I, type II, and type II DTMF receivers are specified. Solid-state
detectors eliminated the need for different DTMF receiver types.
Crosstalks, as well as other transmission parameters are stated to be
specified in a future 478 edition.
Clearly, the standard needs to be updated or rescinded. Just reaffirming it continues wrong and obsolete information as a standard. Rescinding it will eventually cause it to be deleted from the blanket listing of standards at the end of documents. It doesn't belong as a reference for someone wanting to purchase/specify a KTS or related equipment (see 2, 4, 5, 6, 7, and 8 above).