Definity G3 integration with Asterisk

Connecting Digium T1/E1 cards to your Definity G3 PBX

"Do I really need a CSU, loopback jack and special cable to connect my TN-767 or TN-464 card to a Digium T1/E1 card?"

So you want to make an Asterisk box and connect it to your AT&T/Lucent/Avaya Definity G3, and the Definity documentation tells you to buy a 120A integrated CSU and a 700A DS1 loopback jack and an H600-383 cable, right? You don't want to spend the $500, but you do it anyway, and for your efforts you get a Red Alarm on your T1/E1 span. What's going on?

Here's what I've learned the hard way:

1. The H600-383 cable is a straight-through cable and you need a cross-over cable to get rid of that Red Alarm. More on that in a moment.

2. You DON'T need a CSU at all. The only purpose of a CSU is to provide:

a. Loopback capability - not needed for this application
b. Line conditioning - not needed in the 10 feet between your PBX and your Asterisk box
c. Signal boost - your cable is 25 feet long - you don't need to boost anything

3. The 120A integrated CSU limits you to a T-1 bandwidth of 1.544 mbps. If you have a TN-767, you're stuck at T-1 rates anyway, but if you have a TN-464, your TN-464 and your Digium card will happily play together at E-1 speeds of 2.048 mbps. Just get rid of that CSU, and you can jump from 24 channels to 32 channels.

So now you need a cable to connect that 25-pair Amphenol connector on the back of your Definity G3 to the RJ-45 on your Digium TE205P (or whatever span card you bought). Here's how to do it:

- Hold your RJ-45 connector so that the cable entrance end of it is pointed toward the ground and the retainer clip is pointed away from you. The brass contacts are now facing you on the top edge of the connector, right? The first pin on the left is pin 1. The last pin on the right is pin 8. We'll work this end of the cable first. Here we go.

Get a piece of Cat 5 network cable (or better)
- Connect the White/Blue wire to pin 1
- Connect the Blue/White wire to pin 2
- Connect the White/Orange wire to pin 4
- Connect the Orange/White wire to pin 5

Connect the other end of your network cable to the 25-pair Amphenol connector as follows
- Connect the White/Blue wire to pin 48
- Connect the Blue/White wire to pin 23
- Connect the White/Orange wire to pin 47
- Connect the Orange/White wire to pin 22
- Take a spare piece of wire and short pin 49 to pin 24 (the Definity likes to see this shield loop)

You can now connect your Tn-767/TN-464 directly into your Digium card. Goodbye Red Alarm!

Created by: jjohnson, Last modification: Thu 26 of Jan, 2006 (13:56 UTC)
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