PRI Link Issue

So we have an Asterisk PBX with FreePBX. It is connected to our Avaya/Nortel PBX and just serves our department for IVR and such. We recently got a new tech from a new company to service our Avaya system. This tech is scared of Asterisk and obviously doesn't like it. He recently asked me this:

Every night during midnight routing Angel PBX running signaling maintenance test and gives an error message PRI264 DCH: 16 DATA: 00000002 pointing to PRI link between CS1000 and Asterisk VoIP system. PRI0264 message description: Protocol Error: Received an invalid call reference from far-end switch. Output data: DCH: x DATA: y. Where: x = D-channel number and y = Message type. Report problem if condition persists. Severity: Critical I prefer to stop getting this message by correct DCH configuration.

Anyone have any clue? I am not a PBX person, I just know Asterisk pretty well. Here is my configuration:

cat zapata.conf ; ; Zapata telephony interface ; ; Configuration file [trunkgroups] [channels] language=en context=from-zaptel-custom switchtype=5ess group=0 signalling=pri_net rxwink=300 ; Atlas seems to use long (250ms) winks usecallerid=yes hidecallerid=no callwaiting=yes callwaitingcallerid=yes threewaycalling=yes transfer=yes cancallforward=yes echocancel=yes rxgain=0.0 txgain=0.0 immediate=no callerid=asreceived cidsignalling=bell setcallpres=allowed pridialplan=local group=1 signalling=pri_net context=from-zaptel language=en faxdetect=incoming channel=>1-23

I am on FreePBX with Asterisk Appreciate any help or insight anyone can provide.

Possible clue, signalling on channel 16 (DCH: 16) suggests some inkling of a euroisdn (E1) but your channel=>1-23 suggests a NANP T1. check your DAHDI setup and have pri debug on at midnight (intense if necessary). Another suggestion might be to update your dahdi driver, it is probably very outdated.

I also notice you aree using 5ess old fashined AT&T signalling your hardware is probably better matched using NATIONAL2 (or Qsig if you are brave)