* Crossposted in SUPRA
* Crossposted in MODEM
* Crossposted in MODEMS
* Crossposted in SUPRAFAX
* Crossposted in USR_MODEMS
* Crossposted in ZOOM_MODEM
/* [PCMNEWS.TXT]
                                PCM Modem News
                               PCM Modem News:
                      V.90 Is Now The Standard 56K Modem
         Report of the ITU-T Study Group 16 Q23/16 PCM modem meeting
                    relating to 56k modem standardization
              Geneva, Switzerland, January 26 - February 6, 1998
                        Ken Krechmer, Technical Editor
                       Communications Standards Review
The 56K standards wars are over! The technical specifications for a formal
standard (termed Recommendation by the ITU) for 56K modems were completed
February 4, 1998 at the ITU Study Group 16 meeting in Geneva, Switzerland. At
3:36 PM (in Geneva, Switzerland) Thursday February 5, 1998, draft V.pcm was
Determined.(first stage approval). On February 6, 1998 the V series number,
V.90, replacing the working title V.pcm, was released. V.90 specifies a pair
of high speed telephone modems. Generically these modems have been called 56K
[*] or by the proprietary names x2 which is offered by companies led by 3Com
and K56flex which is offered by companies led by Rockwell.
V.90 modems pairs are optimized for Internet access, operating up to 56,000
bit/s from the Internet to the user and up to 33,600 bit/s from the user to
the Internet. V.90 analog is the modem that attaches to a standard PSTN
telephone line and V.90 digital is the modem that attaches to a digital
telephone access service (e.g., ISDN, T1, E1), typically at the Internet
service providerıs site. This configuration is required for operation at data
rates up to 56,000 bit/s.
In record time (March 1997 to February 1998), the ITU completed the technical
specification for this new modem. Now that the technical specifications are
complete, manufacturers are expected to provide upgrades and new products
conforming to draft V.90 before the end of March, 1998. However, draft V.90
will not be finally approved (Decided) until September 15, 1998. V.90
products and upgrades shipped in advance of September 15, 1998 may require
additional upgrades to conform to the final standard. Vendors of the 56K
proprietary implementations have significant field experience with modems
similar to V.90 and compatibility testing between vendors is already
underway. Therefore, upgrades are likely to be adjustments to resolve fine
points of operation between different vendorsı modems and unusual telephone
line conditions. V.90 products are usually software upgradeable, so such
adjustments should be simple for the early purchasers of V.90 products.
Draft V.90 was technically reviewed in detail at this two week meeting and
appears to the experts to be quite stable. Now with the first stage approval
achieved, work is under way to test implementations of the draft V.90
Recommendation and be sure the draft is ready for final approval (Decision).
The V.90 Recommendation document for final approval must be provided to the
ITU by May 11, 1998. Intel has graciously offered to host one, possibly two,
compatibility testing meetings prior to May 11, 1998. All the major modem and
modem chip vendors have expressed interest in participating in this testing.
Any minor editorial or technical changes to the V.90 Recommendation
identified from this compatibility testing will then be included in the
document sent to the ITU for final approval.
This rapid standardization process and easy upgradability ensures V.90 modems
a significant place in the communications access market. V.90 operates over
existing telephone lines without any tariff change and so may be purchased
and used on existing telephone lines immediately. Emerging access
technologies such as xDSL and cable modems, while of considerable importance
in the longer term, require new or modified facilities and new pricing
policies before usage can be wide spread. With a draft formal standard
completed, V.90 modems will quickly become the most common way to access
Internet networks and are likely to remain so for some time.
Dr. Brent Townshend, the Stanford mathematician who invented the V.pcm modem
concept, noted, "Of course, I am very pleased to see the progress towards
formal accreditation of this modem. Without world-wide formal standards, the
value of any communications product is limited." 3Com, the exclusive licensee
of his technology, has agreed under ITU policy to make his technology
available to other companies.
Once again, in Geneva the technical experts have been able to resolve
conflicts that were not be resolved elsewhere. Users, Internet Service
Providers and all modem manufacturers are the real winners from the efforts
of the ITU SG 16 experts.
Ken Krechmer
Technical Editor
+1 650 856-8836
krechmer@ix.netcom.com
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Footnote:
 [*] 56K is an unfortunate moniker, as these modem do not support operation
up to 56,000 bit/s in the existing North American telephone network. Data
rates as high as 53,000 bit/s are currently possible in the North American
telephone network. Changes may be proposed to the FCC Part 68 requirements to
allow data rates as high as 56,000 bit/s.
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*/
Regards, Simon...
ICQ    : 2608849
E-Mail : simon@tcbbs.globalnet.co.uk
webpage: www.users.globalnet.co.uk/~tcbbs/
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