Tech Industry

Voice and data share a wire

Consumers now have another, less expensive way to talk and send data at the same time: Analog Simultaneous Voice and Data modems, which will compete with current Digital Simultaneous Voice and Data technology.

Consumers now have another, less expensive way to talk and send data at the same time: Analog Simultaneous Voice and Data (ASVD) modems, which will compete with current Digital Simultaneous Voice and Data (DSVD) technology.

Diamond Multimedia (DIMD) is one of the first companies out of the gate with this technology. Diamond says it has begun shipping 33.6 kbps ASVD SupraExpress fax-modems for between $129 and $149 that allow users to talk and send data over one phone line.

The difference between the DSVD and ASVD lies in how a user's voice is turned into data. All standard modems take the digital bits of information from a computer and turn them into an analog representation. But DSVD takes the voice stream, digitizes it, then compresses the signal. ASVD takes analog samples of the voice stream and combines them with the modulated data. Less processing is done, and ultimately the product costs less because it needs fewer chips to do its work.

"One thing is for sure, ASVD will cost less than DSVD, and the consumer will be the winner. They will have an [inexpensive] solution that gives them the next generation of voice-data sharing," according to Kieran Taylor, a broadband analyst with Telechoice.

However, DVSD modems offer a performance advantage. The voice data takes up only 9.6 kbps of bandwidth in the DSVD modem, where the voice data in an ASVD modem uses about 14.4 kbps of bandwidth.

Taylor says he believes that there are lower voice data delays with DSVD but that consumers will probably tolerate the difference because of the product price. Data throughput will also be less with ASVD. But he doesn't think this "will be as paramount as some would think."

A typical example of simultaneous communications is talking while changing information on a spreadsheet that all parties can see. Another example is talking and downloading data at the same time.

There are some disadvantages to both products. First, neither is capable of connecting over the Internet--only point-to-point connections can be made. Second, ASVD modems will not be able to talk to DSVD modems unless the DSVD modem also supports the V.34Q standard.

To showcase some of the capabilities of the new modem, Diamond is shipping trial versions of a multiplayer wargame and a whiteboarding and document viewing program. The new modem also supports the V.80 video phone standard for simultaneous transmission of voice and video as well as including videoconferencing software.

The SupraExpress 336 Sp fax-modem with ASVD has an estimated street price of $129 for internal version and $149 for external version. Both require at least a 386 processor.