#format wiki
#language en
= ISDN - digitial phone system =
 * Notes on Cisco ISDN trouble shooting, mostly voice on BRI(2Ch) and PRI(31Ch)

 * Alarm RAI
   {{{
#sh controllers e1 0/3/0
 E1 0/3/0 is down.
  Applique type is Channelized E1 - balanced
  Description: Link to PSTN
  Receiver has remote alarm.
  ...
   }}}
   * Indicates that the remote side (Provider) has a problem and is sending a alarm to the Cisco router interface.
  {{{
#sh isdn status
ISDN Serial0/3/0:15 interface
	dsl 0, interface ISDN Switchtype = primary-net5
	L2 Protocol = Q.921 0x0000  L3 Protocol(s) = CCM MANAGER 0x0003 
    Layer 1 Status:
	DEACTIVATED
    ...
    }}}

...