ITU-T Q.440-1989
Interregister Signalling - General - Specifications of Signalling Systems R1 and R2 (Study Group XI) 4 pp

Standard No.

ITU-T Q.440-1989

Release Date

1989

Published By

International Telecommunication Union (ITU)

Status

Withdraw

Latest

ITU-T Q.440-1989

Scope

Interregister signals are of the multifrequency type using a 2-out-of-6 in-band code in both directions. The multifrequency combinations are sent and received by multifrequency signalling equipment which is assumed to be associated with the registers used

ITU-T Q.440-1989 history

• 1989 ITU-T Q.440-1989 Interregister Signalling - General - Specifications of Signalling Systems R1 and R2 (Study Group XI) 4 pp