Selects the signaling method used for the DS1 link. This mode must match the method used by the network services provider.
Valid Entry
Usage
CAS
Channel Associated Signaling. Out-of band signaling with E1 service. This setting yields 30 64-kbps B-channels for voice or data transmission. Channel 0 is used for framing while channel 16 carries signaling. Used for Enterprise Mobility User (EMU)/EC500 administration.
robbed-bit
In-band signaling with T1 service. This setting yields 24 56-kbps B-channels for voice transmission.
isdn-pri
Either T1 or E1 ISDN service. This setting supports both Facility Associated Signaling and Non-Facility Associated Signaling.
isdn-ext
Either T1 or E1 ISDN service. This setting supports only Non-Facility Associated Signaling.
Note:
NFAS is primarily a feature for ISDN-T1 connections offered by service providers in North America and Hong Kong. However, it can also be used on private-network connections, and in that context it is possible to set up NFAS using ISDN-E1 interfaces.
common-chan
Out-of-band signaling with T1 service. This setting yields 23 64-kbps B-channels for voice or data transmission. Channel 24 is used for signaling.
