Quad Bri Issue

[mitelsx2k]

Hi,
I ahve a site that use embeeded Bri (S bus) i have made up the correct bri crossover cables but the ports stay red when using an isdn2 test butt connected to the end of the x over cable, i have changed the Bri module tried loading the card and intermittently they work once then stop working
Also rebooted the 3300mxe mcd 4.2 , just wondered if there were any settings in the descriptor or Protocol assighnment that i ahve missed.
point to multi point is set to yes and manual TEI is set to no, any help would be very helpful. cheers.

 

[wireman50]

BRI crossover cable ??? nope just a straight cat5 cable here in sunny old england. Pairs 3+6 and 4+5 straight through. Officially you need a 100ohm terminator as well but should work without it.

 

[mitelsx2k]

Thanks for the reply but below is from Mitel


Below from Mitel Knoledge base aticle

When an embedded quad BRI is programmed as "S-Bus Type" the connection to the subscriber equipment must use a x-over cable. The connections are 3-4, 4-3, 5-6 and 6-5. If the correct x-over cable is used then the port LED will be green. If an incorrect cable is being used then the red LED will always be lit.

Cheers

 

[wireman50]

Hmmm, assuming you are using a RJ48 then that doesn't make sense...pins 3+6 are TX and 4+5 are RX you will need 3 to5 and 6 to 4 and 4 to 6 and 5 to 3 or top put it another way 3+6 to 4+5 and 4+5 to 3+6.

In the mitel wiring above you are just crossing over the pairs NOT the TX and RX pairs IYSWIM. That, in my opinion will never work.

 

[wireman50]

and I talking rubbish again sorry, the mitel cable should work

 

[wireman50]

actually I'm not sure as the mitel one may be putting a reversal on the 4+5 RX pos and negative...

 

[bobcheese]

ISDN Xover is correct for S-Bus. However, As Wireman50 I think your PIN outs are wrong, you should have:
3 - 5
4 - 6
5 - 3
6 - 4
Also, you don't mention it but I am guessing you have set them to type 'S-Bus'?

 

[wireman50]

Also just checked my ISDN test butt and that uses a straight through cable (the test butt does the crossover internal depending whether its set to T or S bus).

 

[Supernova99]

You can also use ISDN adapters to crossover on the BRI interface

Try this from RS components
[URL unfurl="true"]http://uk.rs-online.com/web/p/rj-adapters-couplers-extensions/2081742/[/url]

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