ITU/94-16
9 June 1994
ORIGINAL: English
Milestone in modem technology: the V.34 standard is agreed 
by ITU-T and put under ballot for adoption 
Study Group 14 of the International Telecommunication Union - 
Telecommunication Standardization Sector, ITU-T (formerly known as 
CCITT), has been meeting in Geneva, Switzerland for the last week to 
decide on the approval of the long-awaited standard for future high-
speed modems. The meeting was chaired by Mr K. Kern (Germany). The 
work of Study Group 14 covers modems and transmission techniques for 
data, telegraph and telematic services.
The adoption of the standard will give a go-ahead signal to the 
industry to offer new products using high performance data transfer 
technology. Work on the drafting of the standard started some three 
years ago  Termed by industry experts V.fast in its development 
stage, V.34 as it will now be called, will surpass the current 
technology used in data transfer via traditional telephone lines. 
V.34 future modems will transfer data at speeds twice the current 
technology, thus the nickname V.fast. By increasing transmission 
speed, they will drastically cut down the time needed by computers 
and faxes and in turn lower user phone bills. These new modems will 
have variable data transmission capacity ranging from 2 400 
bits/second all the way up to 28 800 bits/second. The new modems will 
use a feature called line probing that will allow modems to identify 
the capacities and quality of the phone line and adjust themselves to 
allow, for each individual connection, for maximum throughput using 
the highest possible data transmission rate. In addition the standard 
will support a half-duplex mode of operation for fax applications and 
will support automoding to existing V-series modems.
Other important features of the new technology include an optional 
auxiliary channel with a synchronous date signalling rate of 200 
bits/second.  Data conveyed on this channel would be independent of 
the primary channel (2 400 - 28 800 bit/second) and would consist 
mostly of modem control data. Multi-dimensional trellis coding will 
be used to gain higher immunity to noise and other phone line 
impairments thus improving throughput. V.34 modems will also be the 
first modems to identify themselves to telephone network equipment 
(handshaking). Most important to the industry, V.34 will not only 
foster world-wide connectivity due to its adaptive capabilities, but 
will enlarge the market opportunities in areas which face poor 
telephone line quality. 
V.34 technology has been long in coming and has had to overcome many 
obstacles.  One year ago, members of the modem manufacturing industry 
had become so impatient, they suggested that an interim standard for 
modems be approved. This interim standard, however, only made speed 
improvements. 
The proliferation of high-speed non-V.fast modem production led many 
market analysts to become sceptical of the interoperability such non-
V.fast technology-oriented products. The adoption of V.34 is 
therefore very opportune. "V.34 modems will be transmission devices 
that will be faster, more reliable and cheaper to use," said Mr Kern 
at the outcome of the meeting.  Given its half-duplex mode of 
operation, the use of V.34 will also help reduce costs of fax 
transmissions and make feasible the use of colour fax. "The fax 
market is in sharp increase on a global basis, thus providing a new 
market outlet for modem manufacturers," Mr Kern added. The approved 
standard should be applicable within a period of 16 weeks maximum. 
"One of the main issues for the future will be to make it possible 
for V.34 modems to adapt their speed while transmitting data to 
adjust with changes occurring on the lines such as noise 
impairments," concluded Mr Kern. 
BREAKTHROUGH FOR DEAF AND HARD OF HEARING
At the same meeting of Study Group 14, a standard - Recommendation 
V.18 - was also approved. It will provide, for the first time, 
recognition of the communication needs of the deaf and hard of 
hearing. This Recommendation, with its capability to interwork with 
all existing devices, provides the platform on which a universal 
standard communication device can be built.
 	A maximum period of one month is required for circulation the 
draft recommendation to the Membership, a three-month period is given 
for the ballot.