Delays introduced by line signalling equipment should be held to a minimum consistent with the requirements covered herein to minimize signal transfer times. Minimizing the delay is especially important in the case of the answer signai and in the case of
ITU-T Q.316-1988 history
1988ITU-T Q.316-1988 PCM Line Signal Receiver - Specifications of Signalling Systems R1 and R2 (Study Group XI) 1 pp