56 kbit/s line

A 56 kbit/s line is a digital connection capable of carrying 56

technology.

Speed derivation

The figure of 56 kbit/s is derived from its implementation using the same digital infrastructure used since the 1960s for

(CAS). This effectively renders the lowest bit of the 8 speech bits unusable for data transmission, and so a 56 kbit/s line uses only 7 of the 8 data bits in each sample period to send data, thus giving a data rate of 8 kHz × 7 bits = 56 kbit/s.

See also

• 56 kbit/s modem
• DS0
• ISDN
• ITU-T V.90
• Switch56

References