Re: Jumper settings for 120 Ohm connection - OpenBSC

28 Feb 2009

Hello Holger,

On Sat, 28 Feb 2009 12:55:04 +0100, "Holger Adams"
&lt;holger(a)kernreaktor.org&gt; wrote:
...

 OK, I think I know where the problem is - there must be a cableing
 problem with the Twinax connectors.

 So there is my next question:
 Which pin of Y01 is TX+ and TX-?
 Which pin of Y02 is RX+ and RX-? 
The polarity does not care, you can exchange TX+ with TX- and RX+
with RX-. A simple test for just the correct wire without connection
the BS-11:

 - On the cable which goes to Y01 you should be able to see a
   signal with an oscilloscop between TX+ and TX-.

 - If you connect the two TX lines with the two RX lines (loopback,
   polarity does not care), the card should synchronise and the LEDs
   should not longer blink. Attention: I have tested this on Windows
   only, with a loopback, I can see that the card synchronises, however
   I don't know what mISDN does, but I guess it will also synchronise.

If this works, you know that the cable is OK.

Best regards,
  Dieter
-- 
Dieter Spaar, Germany                           spaar(a)mirider.augusta.de