ISDN BRI Jumper Settings

[nadamson]

I have a 4 port (8 channel) ISDN BRI card.

There are 8 sets of jumpers, with the option to jumper for 1-2 or 2-3 on each one.

Does anyone have any documentation explaning what these settings are for ???

 

[jerryreeve]

I just pulled a BRI C U4 card and looked at it and have no jumpers at all on it. but there are two areas hidden under a white plastic cover where the jumpers may be. if you are missing the covers then you probably looking at some "factory settings" and may never find documentation on it.

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JerryReeve
Communications Systems Int'l
com-sys.com

 

[nadamson]

The plastic covers are on. On the open area of the card there are 4 rectangle chips marked on the board as T1/T2/T3/T4 (the chips read Pulse PE-65795) next to these are J1 thru J8 which are the jumpers I was interested in.

The board # NT7B7633 REL 01.

Hope you can help.

 

[jerryreeve]

I took another look and I definately do not have those jumpers.

BRI-U4 card
NT 7B87GB 93 rel 2

I pulled the MICS 4.0 IG book though and on Pg 142 found the straps. the straps are termination straps. and the card you have is the BRI ST card

The standard ISDN user-network interface wiring requires termination resistors at each end of the loop for point-to-point operation. this ensures correct timing of the signaling circuits.

Loop termination can be provided at either the point where the ISDN terminal is attached, or by the device attached to the loop (with built-in termination). Because the modular ICS is usually at one end of the loop the BRI-ST card is shipped with termination built-in for each ISDN looop. it is ready to be used where the ICS is located at one end of the loop.

make sure the shorting straps are installed on both the receive and transmit jumpers for the loop. the jumpers are numbered top to bottom, but the loops associated with each pair of jumpers does not follow the same top to bottom sequence: Loop 1 J3 and J4, Loop 2 J7 and J8, Loop 3 J1 and J2, Loop 4 J5 and J6.

this means that when you are connecting BRI telephones to the ICS the termination should be on the ends of the loop. ie on the BRI-ST Card and on the last telephone in the loop.

BTW Strap to left two pins (toward the square transformers) for termination, to the right two pins (toward the back/connector end of the card) to remove termination. no shorting straps also removes termination

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JerryReeve
Communications Systems Int'l
com-sys.com