Dial-Up Modems

 

 

Dial-Up Modems Standard Evolution

 

The International Telecommunication Union (ITU), has standardized modems in order to ensure compatibility of different vendors modems:

 

*    Bell 103 (year 1962) - a full-duplex modem that was capable of 300 bps.

*    V.29 - a half-duplex modem standard, capable of 9600 bps.

*    V.32bis (1980) - full-duplex standard, capable of 14,400 bps and can adjust the data speed to the line quality.

*    V.34 (1994) - doubled the data speed of V.32bis to 28,800 bps.

*    V.42bis - involves data compression and error correction. Capable of 34,000 bps.

*    V.90 (1996) - a standard based on a technology called 56k, and enables (download) data speed of 56 Kbps.

*    V.92 (2000): transmits at the same speed as V.90 but offers a reduced handshake time, faster upstream speed, and an on-hold feature.

 

           


Dial-Up Modems

Dial Up Modem

Dial-Up Modem Network Architecture

Dial-Up Modems Standard Evolution

V.90 Standard

V.92 Standard