When to use a 120 A CSU on a TN464?

[hummer3331973]

Hi-

Just a bit confused: when do you need to use a 120A CSU on a TN464F? I have noticed on this client Prologic that for some, they have their TN464s connected to a 120A CSU but some do not. I was thinking that they have an external CSU/DSU but none. Any ideas?

Those with 120A are connected to the telco, while those without are serving as tie-line to another PBX.

Thanks.

 

[Mitch672]

the 120A CSU has a side effect of making the lights on the front of the TN circuit pack DS1 cards also work, so it is normally used for that, and it also allows the carrier to put the circuit in loop up, so again used their.

It is not needed if connecting 2 PBX's together, as they would not need any protection from each other. It also is not used when you have an E1 circuit such as an IPC Turret (another PBX really), as it does not support E1's, only T1/PRI's



Mitch

AVAYA Certified Expert

 

[4merAvaya]

CSUs, either 120A or external, are to be used when the PBX is connected to the Public Switched Telephone Network (PSTN). This does not apply to point-to-point circuits.

Kevin

 

[dufus2506]

You definitely need a CSU (either the 120A or an external CSU) before you connect to the PSTN.

The 120A and other CSUs are registered with the FCC and are compliant with other countries networks as well. The TN464 card is not an FCC registered device, and has no other homologations. Legally, you're not allowed to connect unregistered devices to the PSTN.

Carpe dialem! (Seize the line!)

 

[hummer3331973]

Ok thanks guys. I'm trying to connect a SIP gateway to a client legacy PBX, so this means no need for the 120 CSU.