[Asterisk-Users] some EICON Diva 4BRI questions

[Armin Schindler]

On Fri, 28 Apr 2006, Klaus Darilion wrote:
> Back to ISDN BRI crossover cable. After reading some ISDN specs I came to the
> conclusion a crossover cable should be:
> 3---4
> 4---3
> 5---6
> 6---5

Yes.
 
> But I also found other pin layouts (e.g.
> http://www.cisco.com/warp/public/788/signalling/bri_voice_port_cfg.html)

I also noticed these other layouts, but e.g. this does not make any sense to 
me.

A BRI port layout is
  3  2a
  4  1a
  5  1b
  6  2b

and the cisco layout would then cross '-' and '+' as well, not just 
the receive/transmit sides.

Maybe this is necessary for cisco phones? I cannot explain that.
 
> Armin, how do you construct your BRI crossover cables?

I use two possibilities.
a) when I want to connect the ISDN card directly with the device using a
   short cable, I just cut the cable in the middle an reconnect them crossed
   and add the resistors here. (Maybe this is not the correct way for 
   termination, but it always worked perfectly.
b) when there is a ISDN bus (cables and plug wall mounted), I just add the 
   cross and terminations to these boxes on the wall.

Armin