Nortel TDM Recorder, Installation Manual

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Configuring Non-Facility Associated Signaling Standard 3.0
80 Nortel TDM Recorder
Non-facility associated signaling overview
Non-Facility Associated Signaling (NFAS) is an extension of the ISDN PRI
interface for T1 and E1. In an NFAS configuration, each trunk span does not
have its own D-Channel. Instead, one D-channel and one backup D-channel
are allocated for a group of trunk spans. In a T1 configuration, this saves a
few extra voice channels that would have been data channels in a normal
PRI configuration.
In order for the TDM Recorder to use the D-channel for tap sense
information, the NFAS configuration must be communicated to the Ai
Logix voice cards. The Ai Logix cards must know which D-channels are
associated with each trunk span. In addition, the D-channel and backup D-
channel spans must be connected to the Ai Logix cards with the lowest card
ID values.
This appendix provides a series of steps that will result in a successfully
configured NFAS environment.