700A DS1 Loopback Jack Function

[telecomadmin12]

I will be connecting two PBXs via an ISDN trunk and I will use TN464GP circuit packs along with 120A4 CSUs. Now on these CSUs I see that a 700A DS1 Loopback Jack must be installed with the unit. Can you tell me what a Loopback Jack is and if it is required for what I want to do?

 

[smokinjoe2938]

a loop back is just for troubleshooting the circuit not needed for what you are doing

 

[telecomadmin12]

Do I need a special T1 cable, or would a simple Ethernet cable do?
Does it have to be a crossover cable?

 

[telcoguy]

Cross or not depends on the other device.
Using brooktrout cards in the past I always had to cross.
For straight a regular CAT5 cable will do.
for cross RJ45 PIN:
1:4
2:5
3:3
4:1
5:2
6:6
7:7
8:8

 

[telecomadmin12]

Thank you.
I will be connecting my TN464HP to a G200 Digium ISDN to SIP gateway. Any idea if the cable has to be cross or regular?