3com 1.024.1644-00 Manuel D’Utilisation

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56K Voice Faxmodem Internal - User’s Guide 

 

V.22 
An ITU-T standard for modem communications at 1200 bps, compatible 
with the Bell 212A standard observed in the U.S. and Canada. 
 
V.22 bis 
An ITU-T standard for modem communications at 2400 bps.               
The standard includes an automatic link negotiation fallback to 1200 bps 
and compatibility with Bell 212A/V.22 modems. 
 
V.23 
An ITU-T standard for modem communication at 1200 bps with a 75 bps 
back channel. This standard is used in the U.K. 

 
V.27ter 
An ITU-T standard for facsimile operations that specifies modulation at 
4800 bps, with fallback to 2400 bps. 
 
V.29 
An ITU-T standard for facsimile operations that specifies modulation at 
9600 bps, with fallback to 7200 bps. 
 
V.32 
An ITU-T standard for modem communications at 9600 bps and       4800 
bps. V.32 modems fall back to 4800 bps when line quality is impaired. 
 
V.32 bis 
An ITU-T standard that extends the V.32 connection range: 4800, 7200, 
9600, 12000, and 14400 bps. V.32 bis modems fall back to the next lower 
speed when line quality is impaired, fall back further as necessary, and 
also fall forward (switch back up) when line conditions improve. 
See online fall back/fall forward  
 
V.34 
An ITU-T standard that currently allows data rates as high as 28,800bps. 
 
V.34+ 
This is an enhancement to V.34 that enables data transfer rates as high 
as 33,600 bps.