SPA400 line voltage issue

Unanswered Question

I have an SPA400/SPA9000 combination which is proving a 'challenge' to get to work on a UK PSTN line.

The SPA9000/400 is showing as registered, on the status screen on the spa400, and on the info screen of the spa9000.

I have connected the UK PSTN line to input 4 (other inputs are all defined as OFFx) and on the status screen a voltage is being displayed.


However, the voltage changes continuously, for example from syslog:

Sep 14 21:51:44 192.168.0.14 0000715174 - TIU: 3 FXO voltage changed, state on, voltage 7V -> 0V^M

Sep 14 21:51:46 192.168.0.14 0000716210 - TIU: 3 FXO voltage changed, state na, voltage 0V -> 24V^M

Sep 14 21:51:47 192.168.0.14 0000716805 - TIU: 3 FXO voltage changed, state on, voltage 24V -> -5V^M

Sep 14 21:51:48 192.168.0.14 0000717304 - TIU: 3 FXO voltage changed, state on, voltage -5V -> 8V^M

Sep 14 21:51:49 192.168.0.14 0000717805 - TIU: 3 FXO voltage changed, state on, voltage 8V -> 14V^M

Sep 14 21:51:50 192.168.0.14 0000718305 - TIU: 3 FXO voltage changed, state on, voltage 14V -> 20V^M

Sep 14 21:51:51 192.168.0.14 0000718804 - TIU: 3 FXO voltage changed, state on, voltage 20V -> 23V^M

Sep 14 21:51:52 192.168.0.14 0000719305 - TIU: 3 FXO voltage changed, state on, voltage 23V -> 7V^M

Sep 14 21:51:54 192.168.0.14 0000720304 - TIU: 3 FXO voltage changed, state na, voltage 0V -> -5V^M

Sep 14 21:51:57 192.168.0.14 0000721804 - TIU: 3 FXO voltage changed, state on, voltage -5V -> 7V^M

Sep 14 21:51:58 192.168.0.14 0000722305 - TIU: 3 FXO voltage changed, state on, voltage 7V -> 11V^M

Sep 14 21:51:59 192.168.0.14 0000722805 - TIU: 3 FXO voltage changed, state on, voltage 11V -> 18V^M

Sep 14 21:52:00 192.168.0.14 0000723304 - TIU: 3 FXO voltage changed, state on, voltage 18V -> 24V^M

Sep 14 21:52:01 192.168.0.14 0000723805 - TIU: 3 FXO voltage changed, state on, voltage 24V -> 17V^M

Sep 14 21:52:02 192.168.0.14 0000724305 - TIU: 3 FXO voltage changed, state on, voltage 17V -> 0V^M

Sep 14 21:52:04 192.168.0.14 0000725305 - TIU: 3 FXO voltage changed, state na, voltage 0V -> -6V^M

Sep 14 21:52:06 192.168.0.14 0000726304 - TIU: 3 FXO voltage changed, state on, voltage -6V -> -3V^M

Sep 14 21:52:07 192.168.0.14 0000726805 - TIU: 3 FXO voltage changed, state on, voltage -3V -> 10V^M

Sep 14 21:52:08 192.168.0.14 0000727305 - TIU: 3 FXO voltage changed, state on, voltage 10V -> 16V^M

Sep 14 21:52:14 192.168.0.14 0000729133 - TIU: 3 FXO voltage changed, state on, voltage 16V -> -6V^M

Sep 14 21:52:15 192.168.0.14 0000730621 - TIU: 3 FXO voltage changed, state on, voltage -6V -> 25V^M

Sep 14 21:52:16 192.168.0.14 0000731121 - TIU: 3 FXO voltage changed, state on, voltage 25V -> 13V^M

Sep 14 21:52:17 192.168.0.14 0000731621 - TIU: 3 FXO voltage changed, state on, voltage 13V -> 0V^M

When i dial in, the SPA400 doesnt answer, and when i try to dial out (using 9xxxxxxxx to route the call) I get a service not available message.

Line impedance is set to 320+(1050||230nF), transmit gain 3db, and receive gain 7db. All of the rest of the configurations is as per the localisation documentation found on this site.

The SPA400 is running firmware -

Firmware Version: 1.1.2.3 - test build AU CID mix

The SPA900 is running 6.1.5

Any ideas?

I have this problem too.
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Patrick Born Tue, 09/15/2009 - 09:36

Hi Steve,

Hmm, the voltage fluctations don't look good.

Just to confirm that there's not some config issue, can you please use the Wizard to configure the system and test again? https://www.myciscocommunity.com/docs/DOC-8126;jsessionid=7AF0BAF23359011FCFF9C1DAD3B4059D.node0

"I get a service not available message."

This could be a clue... do you literally hear a message, "your call cannot be... ... " or similar? If so, this means that you are indeed getting out.

The SPA9000/SPA400 do not play service not available messages.

Could it be that there's a dialplan issue?

   1. Phone dial plan >

   2.     [SPA9000 Voice tab > SIP tab > PBX Parameters > Call Routing Rule:] >

   3.       [SPA9000 > Line N > Dial Plan > Dial Plan:] >

            

Regards,

Patrick

----------

Patrick,


Thanks for you comments.

* the Wizard : I did reconfigure with this version of the Wizard when I updated the firmware of the SPA400 to the Beta indicated.

* The message - This was displayed on the spa942 not via the handset.

One track im following at the moment is that the PSTN line is PSTN, and ADSL via the same cable, and im considering if it is related.

Patrick,

Further testing has indicated something very interesting, and may help towards a final solution for this issue.


I have installed a line splitter between the 'master' socket which is installed by the telephone supplier, and split the line into the circuit to the SPA400, and to a normal phone. This has in effect put a known working device, and the SPA400 in parallel on the phone line.


The voltage is now stable at -47V and the SPA400 picks up when dialled and also makes outgoing calls fine.

So to close off the issue we need to understand what settings in the SPA400 can be changed to enable me to remove the phone in parallel (due to me needing them to be one of the extensions!).

Given that I am using 320 Ohms + (1050Ohms || 230nF) which is Linksys's suggested value, and I have tried 370 Ohms + (620 Ohms || 310nF) as shown in this BT Document (http://www.sinet.bt.com/351v4p5.pdf), and the default of 600Ohms all of which resulted in an unstable line, does Cisco/Linksys have an intel which can help here?

Regards

Patrick Born Tue, 09/15/2009 - 16:57

Hi Steve,

I'm glad to read that you have a working environment. I'm impressed with your resourcefulness.

I'll have a hard time requesting Engineering resources for this. I'll get push-back saying we only support standard PSTN...

Please consider sharing your findings with the phone line provider, perhaps they'll be able to provide a widget that will cause your line to stabilize at ~-48V.

Regards,

Patrick

----------

Patrick,

Many thanks for your generous comments :)

Just to confirm however, there is nothing non-standard about the PSTN line, this is standard BT issue and an PSTN/ADSL is now very very common in the UK.

For example, here is the same issue on another Cisco/Linksys community site : http://forums.linksysbycisco.com/linksys/board/message?board.id=VoIP_Routers&message.id=3932&jump=true

If you can run this issue passed engineering to just see if they have any knowledge of this issue, it would be helpful.


Thanks!

Patrick Born Wed, 09/16/2009 - 14:05

Hi Steve,

My thought is that BT should have an idea why the voltage is fluctuating instead of being -48V.

I'll run it by Engineering.

Regards,

Patrick

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Andrew Hickman Thu, 09/17/2009 - 06:51

Hi Steve,

Do you have access to another PSTN circuit?  Just wondering if you get the same result independant of the line you are using.  What about using a different SPA400 port - did you try port 1?

You mention that this line is broadband enabled - I assume that you are connecting via a filter (basic question I know, but always best to ask :-) ).  Have you tried a different filter?

Do you have anything else connected to your master socket?

I use a SPA400 on a BT circuit connected as follows without these issues - and I don't have anything connected in parallel.

Master Socket -> ADSL Filter -> Single Pair cable -> SPA400 --- IP --- SPA9000.

BTW - have you tried with the released 1.1.2.2 code for the SPA400?

Andy

Andy,

Thanks for your response.


I have tried all 4 FXO ports, all with the same results.

I have had other people suggest that this may be to do with BT Features placed on the line, such as Call Waiting, etc. I am yet to speak to BT as my contact is on holiday and now that I have a valid workaround im happy to wait until he returns.

My setup is very similar to yours, except that I have a BT iPlate rather than a master socket -> Filter setup.

Yes, I have tried 1.1.2.2 and 1.1.2.3 beta both with the same symptoms.

Once I speak to BT, I'll let you know the outcome, as I am aware of other people on other forums who have had/are having the same issue.


Regards


Steve

markatnewclaret Mon, 02/08/2010 - 03:24

Hi,

I have read this and seem to have the same issue.


voltage at the Master socket is -50v, however, the voltage reported by te 400 varies wildly from 0 to -15v. #The result is that the 400 does not respond to incoming and I cant get outgoing.

Is there any more information on how I can stabilise this?

Ive added a splitter and a second phone in parallel with the 400.

Mark,


I never did remove the phone in parallel, so the splitter and the phone are still in place.

Given that this would appear to be a general issue with BT phones and the SPA400, I would hope that CISCO can escalate to their contacts within BT to gain a solution.

CISCO,

If you can do this escalation, I would happily provide the telephone number of the affected line to help resolve the issue.

Regards


Steve

markatnewclaret Mon, 02/08/2010 - 03:38

Thanks Steve but I cant understand how other people cope with this if this is a general issue. It all seems pretty random...

How do I contact Cisco directly or do they monitor this?

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