[Asterisk-Users] Crc4 issues

[Storer, Darren]

Hi Paulo,

PM> This is our 2nd E1 client that we try to use crc4 either with the
PM> e100p or with the e405p without luck.

PM> After some trials, we ask the telco to switch off crc4 on their side
PM> and everything works flawlessly.

[span=1,1,0,ccs,hdb3,crc4,yellow] looks good as it uses CRC4 and sets the
timing to be synchronised with the clock coming in from your Telco's switch.
You do not mention what sort of switch you are trying to connect to and what
sort of physical cabling (including length) is used for connection to the
Telco (Coax, baluns, 120 Ohm RJ45 etc.)???

On the occasions where CRC4 has proved to be a major problem from Asterisk
to the Telco's switch, bad cable termination on the frame proved to be the
problem and as soon as the connections were re-made properly CRC4 worked
perfectly.

I would also refer you to a recent comment from Critch who advised that
Asterisk systems should be power cycled when changing CRC4 and timing
settings for PRI. I agree with Critch _completely_; you must 'init 6' the
system when you make PRI changes otherwise you will obtain false results and
waste a lot of time.

If the comments above do not help perhaps you could provide a bit more
background information and then someone on the list will be able to assist.

HTH

Darren
--
Comgate
Telco>Internet<Broadcast
+44(0)700 COMGATE

-----Original Message-----
From: asterisk-users-admin at lists.digium.com
[mailto:asterisk-users-admin at lists.digium.com]On Behalf Of Paulo
Mannheimer
Sent: 31 May 2004 17:08
To: asterisk-users at lists.digium.com
Subject: [Asterisk-Users] Crc4 issues


Hi All,

This is our 2nd E1 client that we try to use crc4 either with the e100p
or with the e405p without luck.

After some trials, we ask the telco to switch off crc4 on their side and
everything works flawlessly.

Is there anything in the crc4 calculation that may be broken? We took a
look at wct1xxx.c and wct4xx.c but there doesn't seem to be much there
to be fixed (apparently the crc4 calculation is done within the chip
itself).

We also took a look at
http://lists.digium.com/pipermail/asterisk-cvs/2003-September/000126.htm
l but couldn't figure out what bits should we try to set to test other
card options.

Is there any documentation on the card that could help us?

Our zaptel looks like ...

span=1,0,0,ccs,hdb3,crc4

bchan=1-15,17-31
dchan=16

We already tried ...

span=1,1,0,ccs,hdb3,crc4
span=1,1,0,ccs,hdb3,crc4,yellow
span=1,0,0,ccs,hdb3,crc4,yellow


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