BT isdn30 digium Te205p Grandstream gxp 2000 Noise on line

Asterisk Asterisk Support
1

Hello

Can anyone give some help with the following 2 problems Im having on a system which we are testing before it goes live in a few weeks. I have tried to include setup details below.

My setup consists of:

P4 3.2ghz 2gb Ram
Adaptec Scsi raid card (raid 1)
1x te205p e1 card for our uk Bt isdn30e line. (23 channels)
2x tdm400 for 8 analogue lines. (lines linked to some mobile phone dock n talks but only few calls on these per day)

The cable between the e1 card and the BT isdn box runs over some offices so its around 75 feet long. (made just with normal rj45 cable and 2 crmp plugs not shielded).
(CAN ANYONE TELL ME IF THIS IS OK LIKE THIS ??)

Software consists of Redhat FC3 with all the updates and Zaptel 1.2.9.1 (mark2 echo and aggressive echo cancelation enabled) and Asterisk 1.2.11

I also have 55 grandstream gxp phones(half have the latest firmware 1.1.14) Gxp2000 uses the ulaw codec.
Also the windows workstation pcs connect via the passthrough rg45 port.

Our network is made up 1 main gigabit switch which our servers are on ie web-email-file and 2 smaller switches with 1gig uplink to the main one which most of our telesales are wired to 100mb.

Overall the system works very well except for the following 2 problems which im now a bit stuck on what to try.

The problems we seem to get are replated to calls on the isdn30 line:

Line Noise:
We quite often can hear a crackle on the gxp2000 handset which is worse when we turn the volume up.?

Headsets.
We have the VXI Passport Headsets 10V and 20V and customers are always saying that the sound they hear is breaking up which makes for a poor call. I have tried the rx-tx gain using the ztmonitor util.?

Do you have to use headset amps?

RX can be between 40-100% on different incomming calls
TX is normally around 30-40% increasing tx gain does not make much change.

My config settings are:
zaptel
[channels]

language=en
usecallerid=yes
hidecallerid=no
callwaiting=no
callwaitingcallerid=yes
restrictcid=no
usecallingpres=no
threewaycalling=yes
callreturn=yes
transfer=yes
cancallforward=yes
echocancelwhenbridged=yes
echocancel=yes

musiconhold=default
rxgain=2.0
txgain=3.0
signalling=pri_cpe
switchtype=euroisdn
immediate=no
overlapdial=yes
pridialplan=unknown
prilocaldialplan=unknown
group=1
context=incoming
callerid=asreceived
channel => 1-15,17-25

Zaptel

loadzone=uk
defaultzone=uk

span=1,1,1,ccs,hdb3,crc4
bchan=1-15
dchan=16
bchan=17-31
loadzone=uk
defaultzone=uk

Anaglogue lines config left out.

Thanks

Nick Colyer

2

I have just found out from searching on goole re isdn 30 cable.

one site for some call logging equipment says if you need to make a longer
isdn 30e cable max 100feet then you should always use shielded rj45 ftp cable.

As our current cable is unshielded and runs through a loft full of mains/mobile rf cables and other network cables this could be my problem.

I have ordered a box of shielded cable and shielded crimp plugs so will try it on monday night.

Has anyone used headsets with the gxp 2000 phone?

Nick

3

Hi Nick

Couple of things from a scan of the post.

Change the phones to alaw, we are not in the US or Japan and it will be one less transcoding delay.

set any gains on the trunks to 0

consider swapping handsets for a business grade set.

As to the cable, The spec allows upto 200 feet of unscreened, But I must admit that in cases over 20feet I have used screened. Are you seeing any errors or slips ?

The next stage is to swap the cable, then do a bit os sniffing on the nework to see if there are any lost packets. sineapps have a useful test tool, its iax but will show up any internal problems. If the second port is not in use on the e1 card, Use that and connect it to a test set.

4

Hi

Thanks for the info.

I will have to try it on monday

I can set the phones to alaw and try the rx and tx gain on the isdnline to zero and see what happens.

We are stuck with the gxp2000 and I know they are sold as business grade but at the lowest end of the market.

Re line errors - Im not getting any line errors but I do know the cable does run over several mains and alarm cables in the loft and we also have a mobile phone repeater amp near the cable.

I have typed ifconfig eth0 and it does not show any lost packets on the network device but i will have a look at sineapps.

Thanks

Nick

5

Ops just checked and asterisk is already set to only allow alaw.

Nick

6

Hm

The sinapps “tester” is at sineapps.com/sinestatiax.php

If it is the ISDN you would expect to see slips or CRC errors.

What does zttest show up when under load ? also top as well.

Ian

7

Nickcol

we had a one story (but a bit all over the place directionally) run between our BT NTE equipment and our asterisk server for at least 4 months till the relocation of the comms rack. Ran down thru comms ducting but I think it was just regular cat-5 rather than shielded. Also load of electric and power stuff in a simlair riser cupboard but no real issues.

Personally I’d try beg/borrowing/stealing another phone for testing. I certainly was ‘warned off’ the grandstreams by my installers who had done quite a few deployments. We use the snom 190s which are pretty good. Can’t say I was overly enamoured of the headsets however (despite them being plantronics IIRC) - most of our agents (who are not permanently on the phone) have switched back to handsets.

8

Hi,

I have replaced the rj45 cable with shielded rj45 without any change. I thought it would not change anything after speaking to some people.

Because internal phone to phone calls are clear and good and the sound problems only affect calls which go in/out through our digium e1 card im sure its a m/b problem or digium card problem.

I am replacing the m/b thursday with a supermicro board and new cpu and ram, Just hope this solves the problem. If we still have the problem then i would have to get another digium e1 card.

Nick

9

Last night I replaced the motherboard in our asterisk server with a Supermicro P8SCT-0 board with a intel p4 3.2ghz and 2gig of ram.

After a busy morning of calls today our customers have had no fading or breaking up of sound like before so looks like it was the motherboard causing all the problems.

Thanks for the help

Nick

10

sorry didn’t see your previous post otherwise I would have said go for it on the supermicro board. We’ve been running our box on it for over 18 months without any real dramas.