V.92 Modem Software
Features of V.92 Modem Software (V.92 soft modem)
- Duplex mode of operation on the PSTN
- Channel separation by echo cancellation techniques
- PCM modulation in both directions at a symbol rate of 8000
- Synchronous channel data signalling rates in the downstream direction from 28 000 bit/s to 56 000 bit/s in increments of 8000/6 bit/s
- Synchronous channel data signalling rates in the upstream direction from 24 000 bit/s to 48 000 bit/s in increments of 8000/6 bit/s
- Connection time for V.92 will be up to 50% quicker than V.90
- Adaptive techniques that enable the modems to achieve close to the maximum data signalling rates the channel can support on each connection
- Negotiate V.34 modulation upstream (downstream) if a connection will not support PCM modulation upstream (downstream)
- Exchange of rate sequences during start-up to establish the data signalling rate use of V.8, and optionally V.8 bis, procedures during modem start-up or selection
- Use of V.8, and optionally V.8 bis, procedures during modem start-up or selection
- Reduced start-up time on recognized connections
- Support of modem-on-hold procedures in response to call-waiting events or outgoing call requests
- V.92 has the ability to temporarily put the 'Modem On Hold' (MOH) allowing users to receive a phone call without having to disconnect from their Internet session.
Advantages of Software Implementation
OEMs need to get their products to market quickly. They must also make sure these products are upgradable to any new versions of the ITU V.90 standard that may be released. Hardware implementations of V.90 modems will be much more difficult to upgrade than software implementations. A software implementation on a DSP is not only upgradable; it also allows multiple functions to run on one processor. This gives the designer flexibility in product design as well as a better cost/performance ratio. GAO Research offers quality modem code ready for licensing providing a quick time-to-market.