V.92

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V.92 is an ITU-T recommendation, titled Enhancements to Recommendation V.90, that establishes a modem standard allowing near 56 kb/s download and 48 kb/s upload rates. With V.92 PCM is used for both the upstream and downstream connections; previously 56K modems only used PCM for downstream data.

V.92 was first presented in August 1999. It was intended to succeed the V.90 standards; however, with the spread of broadband Internet access, uptake was minimal.

New features[edit]

Quick Connect[edit]

This reduces negotiation times to around 10 seconds instead of over 20 seconds. Quick connect works by training the client modem on the first call; analog and digital characteristics are stored in a local profile and then retrieved for future connections.

"Modem on Hold" (MOH)[edit]

This allows the connection to be temporarily severed and then reconnected, reducing the possibility of dropped connections. This is particularly useful for lines that have call waiting.

PCM upstream[edit]

Pulse-code modulation (or PCM) allows higher rate digital transmissions over the analog phone lines. PCM upstream provides a digital connection for upstream data, reducing latency and allowing for a maximum upload speed of 48 kbit/s. Previously the speed was limited to a 33.6 kbit/s analog signal under the previous V.90.

V.44 compression[edit]

V.44 compression replaces the existing V.42bis compression standards. It generally allows for between 10% and 120% better compression. In most situations the improvement is around 25%.

See also[edit]

External links[edit]