DX digital card acting up

[blastman]

hey all,

We have a DX system and have reached the full capacity of analogue cards.

We have recently had a digital card put in which gives us an extra 16 extensions.

When the phone engineer was installing it he showed me how to double the extension up by adding a a virtual number to an existing number.

Since we have now again run out of extension I have started doubling up to give us some extra numbers.

My problem is that every few days, some of the digital users phones start displaying 'line out of service' and I have to change the A-B settings on the model 70 phones.

It's almost as if the polarity of the A and B settings is being reversed on the switch by it's self!

Whats more is that it doesn't happen to everyone and more often than not it's the people who haven't had their phone doubled up that experience this issue.

Has anyone got any ideas as to what might be causing this or any suggestions as to how I can try and diagnose it further??

Thanks for taking the time to read this.

Blastman

 

[blastman]

apon further looking I've noticed that there are a load of 93n and 82 0001/2 errors


Any ideas anyone?

 

[pablo100]

It looks as though you are running the Rdx DTi cards and the siemens D.96 range of propietory isdn phones ( i.e. Realitis model DT 40/50/60/70)

From the hardware error codes that you have postedit looks as though there is a mismatch between the 'A/B' settings of the phones that are conected to the DTI ports ( labeled as'A1,A2 etc in the software)

You can run two telephones from each physical port on the DTI card as long as each phone has the A/B switch set correctly = i.e, one phone with switch set as A the other one set as B or vise/versa.

The A/B switch is located underneath the phone in a recess where the handset curly cord is plugged in.

Assuming that the phone is laying face down and the part code label is the correct way up, the A setting is with the switch to the left, and the B setting is with the switch to the right.

Normally the DTI line splitted at the outlet nearest to the pair of telephones that are being run, however it is possible to split the DTI line ( or access Ax ) in a riser cupboard at a cat5 patch panel up to 100 metres away form the phones assuming cat5e cabling.

As regard to a solution, i would suggest that you disconnect one telephone from each of the accesses that are running two telephones, wait for any associated errors to be flagged as passed on that access, then one at a time reconect the phones with a different switch setting one at a time, checking error codes and making test calls inbetween connecting phones.

Be methodicall and check each access at a time.

Hope this helps

pablo100

 

[blastman]

Hi,

Thanks for the reply.

I've used ldti to show all the cards and the extensions on them and then wrote down what A/B setting the switch thinks they should be on.

I then walked round and checked all the phones and made sure all of them where correct (which they were)

I have now just cleared the hardware error log so if the users report these issues again I can what error and when.

So far so good.

No-one has reported anything this moring, so fingers crossed.......

 

[ninety9]

Have you checked that the circuit has an end of bus resistor on it. Not one per phone but one per channel. This normally comes in the form of an ISDN line adaptor mod-tap. It needs to be installed in line before the channel is "split" for the 2 handsets. Absence of these e-o-b resistors will result in all sorts of problems.

Alternately the A/B allocation if not completely right will result in occasional working and intermittent faults, as detailed in other answers