NEAX2400 IPX ISDN Features and Specifications
NDA-24311, Issue 1 Page 129
Tandem Switching of Tie Trunks - 2/4-Wire - PRI T-37
T-37 Tandem Switching of Tie Trunks - 2/4-Wire - PRIGeneral Description
This feature allows PRI trunk-to-tie-trunk connections through the NEAX2400 IPX, without the need for any
Attendant assistance or control. The major use of this feature is in association with the Dial Tandem Tie Line
Network to allow Tie line connections and incoming Tie line calls automatic access to, and completion of, local
Central Office calls.
Operating Procedure
1. Lift the handset; receive dial tone from the distant office.
2. Dial the Tie trunk access code; receive dial tone from the NEAX2400 IPX.
3. Dial 9; receive dial tone from the distant PBX or local Central Office.
4. Dial the Central Office exchange number (local or toll).
Service Conditions
1. When using the 2-wire application, there may be an appreciable decrease in transmission decibel levels.
2. The 4-wire E&M Trunk package provides amplification/attenuation, so that the desired transmitting and
receiving levels can be maintained, providing the overall tandem system with transparency.
3. When Tie trunks are busy, the calling station receives busy tone.
4. Each incoming Tie trunk can have various restrictions for Tie Line-to-Central Office calling.
5. Careful consideration should be given to access code numbering plans t o avoid un necessar y loss of access
codes and code duplication within the same system.
6. Tandem switching can also be accomplished via the ATTENDANT CONSOLE [A-3].
7. There is no limitation to the allowable number of tandem switching connections.
Interactions
1. TOLL DENIAL/TOLL DIVERSION [T-6]: If TOLL DENIAL is applied to an incoming Tie trunk group,
the calling user is routed to reorder tone if an attempt is made to dial-access a toll call.
2. The TOLL RESTRICTION - 3/6-DIGIT [T-7] feature is assigned on a per incoming Tie trunk group basis.
The distant calling user is routed to reorder tone if an attempt is made to dial a restricted number code.
3. STATION MESSAGE DETAIL RECORDING (SMDR) [S-10]: On tandem connections, the incoming
Tie trunk group route number and outgoing trunk number are recorded.
4. Two outgoing trunk group restriction tables are provided per system. The Direct Dial Access table is
indexed when a distant user dials the trunk group access code, and the ATTENDANT CONSOLE [A-3]
table is indexed on Attendant completed calls.