11-29-2009 06:47 PM
I have a Linksys VOIPAdapter SPA-2102 which worked fine for two years but started ‘duplicate digitdialing' from mid-October this year. While it is still working perfectly for callsto and from any US/Canada number, now it always dials "double digits"randomly AFTER getting connected to an international access number(403-260-3325) and then dialing 011 to connect overseas . For example, aftergetting connected if I dial 92-51-2256684 it instead dials 922512256684or 925512256684 or 992512256684 etc. Thus the problem startsafter dialing 13 digits, while the same settings worked fine earlier for twoyears.
I have talked extensively both to my VOIP phone service provider and theInternational Dialing service provider, but both have failed to solve theproblem. The problem is not faced if I use a softphone from my computer,confirming the problem to be in the VOIP Adapter settings. I changed my phonebut that has not solved the problem. I reset the VOIP Adapter to defaultfactory settings by dialing the 73738# code from the handset and then feedingin the settings provided by my service provider (Adminlogin-Advanced-Voice-Line 1) but problem was not solved. Tried the same with877778# code but problem stayed. Downloaded the firmware from Linksys(Cisco)website and upgraded to version 5.2.10 from 3.3.5(a) but problem still there.
Can someone help, as I amunable to dial overseas since last six weeks!
11-30-2009 09:30 AM
It sounds like you are experiencing difficulty transmitting dtmf digits across the internet. The SPA2102 has several protocol settings for transmitting dtmf: Inband, AVT, INFO, AUTO and combinations of Inband, AVT, and INFO. Generally AVT, which is RFC2833, is the setting that works best although that is not always the case. I would run some tests, starting with AVT, to see if setting changes make any difference.
There is also a setting for how long you need to press the phone key for the adapter to recognize it as a key depression. This is DTMF Tx Mode Strict or Normal. With the Strict setting you need to depress the key for a longer time.
11-30-2009 09:58 AM
Thanks hw for your kind advice.
In fact I had earlier tried out INBAND, AVT, INFO and their various combinations but none worked (the default is Auto, and that is also not working). The DTMF Tx Mode is on Strict by default and that in worst case should lead to lesser number of digits dialed-rather than the greater number of (unwanted duplicate digits) dialed.
Irony is that the ATA is working ok for all calls to and from all North American phones.
Would appreciate any further advice in light of this.
Thanks and regards
11-30-2009 12:19 PM
11-30-2009 01:35 PM
The softphone that worked was X-Lite version 3.0 build 53621. It only required filling in the Display/User/Authorization User names, password, domain and Dial Plan.
The rates offered by my 'international' call provider (Comwave) to Pakistan are 5.9 Canadian cents per minute, by my VOIP provider (Acanac) 32 Canadian cents per minute, by onesuite.com 27 US cents per minute and by callcentric.com 10.4 US cents per minute. Thus Comwave is significantly lower for frequent calling to know about safety of loved ones in view of the conditions in Pakistan.
11-30-2009 03:05 PM
You cannot use tcp unless your voip provider supports it and very few of them do support it.
By default XLite sends dtmf with RFC2833 and G711u codec which is the AVT setting on the SPA2102 with the G711u codec preferred.
If you do not have XLite registered to your voip provider, but have it registered instead to your international provider then the comparison is not the same. This is because with the inital call the dtmf digits are not sent as part of the call, with the initial call the number to be dialed is sent as part of the sip invite which is a signalling data packet.
Your SPA2102 has two separate voip lines (for two separate phones). You should consider registering one of the lines to your international provider.
12-01-2009 10:19 AM
Thanks hw for your persistent help.
I have tried G711u and G729 with AVT but none worked.
I want to add some more data which may enable better diagnosis.
Thanks and appreciate your continued generous support.
12-01-2009 04:00 PM - edited 12-01-2009 04:08 PM
12-01-2009 08:39 PM
Thanks again for hw knight to the rescue.
I fully agree with you, but the dilemma is that the international call provider says that it is receiving 'duplicate digits' from my phone provider side and cannot do anything about it while the VOIP phone provider says that the fact that there is no problem with softphone shows that the ATA is the source of problem. I want to use the phone to call, and not be strapped to computer mike/headset. Clueless as to why the SPA2102 is functioning ok except this problem which is not replicated on softphone. There has to be a logical reason that is evading so far. Purchasing a new ATA is no guarantee that it would work (I spent $120-incl tax and shipping on the present one). The international call provider does not agree to provide a VOIP line unless I contract for a year @$29.95 per month (the present one charges $9.95 Canadian $ per month unlimited to US/Canada). Having tried my best with limited knowledge, I can only hope and pray for a miracle solution. Its SOS now ! Any brainstormed solution to tweak the settings is welcome.
12-01-2009 10:27 PM
If you tried the different combinations of DTMF Transmit Method and Codec settings you tried the obvious fixes.
To persue further changes, I would download the latest firmware for the SPA2102, install it and re-enter your configuration. If you are currently running the latest firmware, I would reset the firmware to factory specifications with the IVR and re-enter your configuration. You can download the latest firmware here:
When you send dtmf digits using the rfc2833 protocol, for each digit the protocol sends a start digit packet, then multiple packets for the digit depending on how long you hold down the key, then an end packet. If the packets get out of sequence or lost that's when the receiving end can get an error in decoding the digit. The packets are sent along with the voice stream packet (rtp packets). If you made the call with XLite using the same voip provider to call the pstn number and experienced no problems whereas you consistently experienced problems with the SPA2102 then it would seem that the firmware in the SPA2102 has some difference with the XLite computer code. As I said, by default it appears to me the XLite is using rfc2833 as a dtmf transmission method and G711u as the codec.
Several of the Betamax companies have competitive promotional rates to Pakistan. VoipBuster is 3.0c/min, Rynga is 3.0c/min, Jumblo is 3.0c, 12voip is 3.5c/min, budgetsip is 3.3c/min, and actionvoip is 4.0c/min. These are euro cent prices. You could try one of these companies with your 2d line on the SPA2102. The disadvantage here, though, is it costs 10 euros to get started which is close to $16 Canadian, they can change the rates without warning, and they offer zero customer support.
You could also try a different voip provider to call the pstn number as a test to see if that made any difference. You can get a pay-as-you-go account with CallCentric for a $5 (US) deposit. With CallCentric, calls to a Canadian PSTN number are 0.0198 (US) per minute.