SL_SIGNALLING_LINK_MODE

This enumeration defines the signaling link mode of a common channel signaling trunk.

This describes the characteristics of the signaling. A configuration where several T1 facilities are controlled by a single signaling channel, is called non-facility associated signaling (NFAS).

SL_SIGNALLING_LINK_MODE_INVALID

The specified common channel signaling mode is invalid.

SL_SIGNALLING_LINK_MODE_PRIMARY

The trunk carries a primary common channel signaling link. Examples include:

• Each primary rate interface in an E1 ISDN configuration.
• The trunk in an E1 SS7 configuration, carrying the signaling link.
• The primary rate interface in a T1 non-facility associated signaling (NFAS) ISDN configuration, which is carrying the primary D channel.

SL_SIGNALLING_LINK_MODE_BACKUP

The trunk carries a backup common channel signaling link.

• The trunk in an E1 SS7 configuration, carrying the backup signaling link.
• The primary rate interface in a T1 non-facility associated signaling (NFAS) ISDN configuration, which is carrying the backup D channel.

SL_SIGNALLING_LINK_MODE_NA

The trunk does not carry a common channel signaling link. Examples include:

• An ISUP trunk in North America, which is only carrying voice traffic, while the signaling is carried over a separate A-link.
• The trunks in an ISDN NFAS configuration which are carrying only 24 voice channels.
• The trunks in an E1 SS7 configuration which are only carrying traffic channels.