[Webinar] Learn how to a build a cloud-first strategyRegister Now

x
?
Solved

Asterisk, Digium TDM400 FXO, & Phantom Rings

Posted on 2006-06-12
3
Medium Priority
?
784 Views
Last Modified: 2008-02-01
We have set up a customer with an Asterisk @ Home 2.8 system (went in before Trixbox was out). It has four BT lines (we're in the UK) connected to four FXO ports on a Digium TDM400B card. The only advice/help I have had was to add OPERMODE=UK which I did - and it made the problem worse.

The problem is that at the end of just about every call, the system acts as though there is another call coming in. I believe this is caused by a battery drop or polarity reversal on the line to signal call disconnect being detected as a ring signal due to too little debounce.

How do I fix this, it's driving the client mad !
0
Comment
Question by:FurnessSupport
  • 2
3 Comments
 
LVL 19

Accepted Solution

by:
feptias earned 1500 total points
ID: 16894713
I don't use @ Home so this info might not be relevant, but I noticed the following in my sample zapata.conf file:

; In some countries, a polarity reversal is used to signal the disconnect of a
; phone line.  If the hanguponpolarityswitch option is selected, the call will
; be considered "hung up" on a polarity reversal.
;
;hanguponpolarityswitch=yes

There is also some choice about signalling on analogue lines. This is also copied from zapata.conf:
; fxs_ls:         FXS (Loop Start)
; fxs_gs:         FXS (Ground Start)
; fxs_ks:         FXS (Kewl Start)

I use Kewl Start for an FXO line in UK and it doesn't give the problem you described. However my analogue line might not use exactly the same signalling as yours. Also, my system doesn't detect any hangup signal from the exchange so the line is left open until the local extension clears the call. Not ideal, but better than phantom ringing.
0
 
LVL 1

Author Comment

by:FurnessSupport
ID: 16895155
Thanks for that, having the hanguponpolarityswitch keyword would have probably been enough to find what i was looking for with Google. As it is, I've just had an email from Digium (after I'd given up on waiting for an answer) to tell me I need :

answeronpolarityswitch=no

I've set it on the cusotmers system and it seems to work - just waiting to see if it causes any other unexpected problems.

Now, to find somewhere to put the information so that other might find it in future !
0
 
LVL 19

Expert Comment

by:feptias
ID: 16895244
I saw the other parameter, answeronpolarityswitch, but I just assumed it would take a default of "no". It is a bit surprising that the default is "yes" because battery reversal is not commonly used to signal ringing that I'm aware of.

I'm glad you've got a solution and thanks for the points/feedback.
0

Featured Post

Keep up with what's happening at Experts Exchange!

Sign up to receive Decoded, a new monthly digest with product updates, feature release info, continuing education opportunities, and more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In my office we had 10 Cisco 7940G IP phones that were useless as they were showing PROTOCOL APPLICATION INVALID when started. I searched through Google and worked for a week continuously on those phones, and finally got them working. This is a di…
Every year the snow affects people and businesses. According to the Federation of Small Businesses (FSB), in 2009, UK businesses lost an estimated £1.2bn (http://news.bbc.co.uk/1/hi/business/7864804.stm) because of bad weather. This article was c…
Please read the paragraph below before following the instructions in the video — there are important caveats in the paragraph that I did not mention in the video. If your PaperPort 12 or PaperPort 14 is failing to start, or crashing, or hanging, …
As many of you are aware about Scanpst.exe utility which is owned by Microsoft itself to repair inaccessible or damaged PST files, but the question is do you really think Scanpst.exe is capable to repair all sorts of PST related corruption issues?
Suggested Courses

864 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question