4B3T Hear it!

4B3T (4 Binary 3 Ternary) Telecom Definition

A line coding technique used in European and many other countries outside North America for ISDN basic rate access (BRA). 4B3T combines four bits to represent one ternary signal state. Therefore, the baud rate is three-fourths of the signaling rate, and ISDN BRA at 160 kbps requires a baud rate of 120 KBaud. 4B3T yields shorter ISDN transmission distances than 2B1Q, but distances in Europe and elsewhere often are much shorter between the central office exchange (COE) and the customer premises. See also 2B1Q, baud rate, BRI, COE, ISDN, and signaling rate.