pushp@nic.cerf.net (Pushpendra Mohta) (08/16/90)
I wonder if some one has an on-line copy of V.35 specs . --pushpendra CERFNEt
tnixon@hsfmsh.UUCP (Toby Nixon) (08/18/90)
In article <143@nic.cerf.net>, pushp@nic.cerf.net (Pushpendra Mohta)
asks:
- I wonder if some one has an on-line copy of V.35 specs.
I don't, but I want to point out something. V.35 is a standard for
a 48,000bps group-band modem. It is not, and never has been, and
"interface standard", which is what most people mean when they talk
about "V.35". An appendix to V.35 described electrical
characteristics for a serial interface, but didn't even mention a
connector (and most people are referring to a connector when they
refer to V.35).
CCITT Study Group XVII has discontinued support for and publication
of V.35, because it is obsolete. V.10 and V.11 describe the
electrical characteristics one should use. There is still no
standard defined for the connector, although ISO/IEC JTC 1/SC 6/WG 3
is working on such a standard. V.36 and V.37 describe more modern
group-band modems, if that's really what one is looking for.
If one is looking for a modern interface standard for high-speed
devices, ANSI/EIA-530 is ideal. It uses the traditional 25-pin
D-shell connector, but the V.10/V.11 (EIA-422/423) electrical
characteristics, and can handle up to 2 megabit data rates at 1,000
feet.
If you REALLY NEED V.35, you'll have to find specs from one of the
companies that makes "V.35" devices, such as IBM. There is nothing
in the national or international standards that describes the "total
package" of electrical characteristics, pin assignments, and connector
physical characteristics.
-- Toby
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-----------------------------------------------------------------------------csg@pyramid.pyramid.com (Carl S. Gutekunst) (08/28/90)
[I am used to concise and useful postings from Toby. The petulant tone of this one surprised me. Generally I don't waste time correcting inaccurrate postings on this net unless they are from someone I respect.] >In article <143@nic.cerf.net>, pushp@nic.cerf.net (Pushpendra Mohta) asks: >- I wonder if some one has an on-line copy of V.35 specs. I do not believe you will find one; I've looked long and hard for *any* online CCITT, CEPT, or ISO documents, without success. CCITT and ISO docs are almost exclusively provided on paper through Omnicom, who charges truly outrages fees for them. In article <3842@hsfmsh.UUCP> tnixon@hsfmsh.UUCP (Toby Nixon) writes: >V.35 is a standard for a 48,000bps group-band modem. It is not, and never >has been, and "interface standard", which is what most people mean when they >talk about "V.35".... CCITT Study Group XVII has discontinued support for >and publication of V.35, because it is obsolete. This is all true, but utterly irrelevant. The electrical interface described in Appendix I of V.35 is not only widely implemented, but is also called out explictly in CCITT X.21bis. (CCITT still persists in referring to X.21bis an "interim" standard, which is pretty silly on the face of the evidence.) Also, many certification bodies either support or mandate it, including DOD, CEPT (Europe), and JATE (Japan). >There is still no standard defined for the connector.... Not true. The standard recognized by both CCITT and CEPT is ISO 2593. While it is true that there is no *single* document from any of the standards bodies that defines the entire interface colloquially known as "V.35," it is not difficult to assemble the four that you need for a complete definition: ISO 2593, V.35, V.28, and V.24. There is nothing magic about this list; each of the higher level documents makes clear references to the lower. Incidentally, there is no single CCITT document that defines RS-232, either; you need ISO 2110, V.28, and V.24. That the V.35 interface is scattered over four documents in not unusual in this game. >V.10 and V.11 describe the electrical characteristics one should use. Most of us know these as the physical level of X.21, so much so that they have colloquially become known as X.21. These *are* the CCITT-preferred interfaces for any high-speed application. But just try to find vendors that implement them! Most are in isolated communities (usually enforced by PTTs), in Western Europe and Japan. But not much anywhere else in the world. If you implement a V.10/V.11 interface, you will find little iron that can talk to. Implement the V.35 interface, and you can talk to almost everyone. But Todd's real point is well taken. If you are designing something new, from scratch, you'd do well to implement V.10/V.11 first, and V.35 after. I don't doubt that much more V.10/V.11 equipment will be available in the future. It is a major hassle right now for Pyramid selling into Europe not to have X.21. <csg>
a186@mindlink.UUCP (Harvey Taylor) (08/31/90)
In <124917@pyramid.pyramid.com> csg@pyramid.pyramid.com (Carl S. Gutekunst) writes: | | CCITT and ISO docs are almost exclusively provided on paper through | Omnicom, who charges truly outrages fees for them. CCITT docs are also available from Global Engineering Documents and the United Nations. The Series V recommendations (The Blue Book -VIII.1) costs US$51.80 from the UN and about US$80 from Global. Omnicom, 115 Park St. SE, Vienna VA 22814 USA, (703)281-1135. United Nations Bookshop General Assembly Building Room: G.A. 32B New York, NY 10017 USA (212)963-7680 Global Engineering Documents 2805 McGaw Irvine, CA 92714 USA (714)261-7892 You choose. <-Harvey "If men could get pregnant, abortion would be a sacrement." -Florence Kennedy Harvey Taylor Meta Media Productions uunet!van-bc!rsoft!mindlink!Harvey_Taylor a186@mindlink.UUCP