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[Equipment] Excessive Line noise


I have a polycom phone connected to a freeswitch server that uses a spa 3102 ata that in turn is connected to a skype connect me box, When I have a call going through the skype box, I get a lot of hum and reduced audio quality.

I on a US land line and was wondering if I might want to adjust some of the pstn parameter to try to clear up the noise. When the skype box wasn't connected meaning the spa 3102 went direct to the land line, I didn't have any noise issues.

any suggestions ?


I don't believe that changing SPA3102 settings will help.

Reversing the AC power plug (swapping hot and neutral) on the SPA power adapter, the Connect-Me power adapter, or both may reduce the hum level.

If you temporarily disconnect the landline from the Connect-Me box, does the hum level improve?

Possibly, connecting the common (negative) output from the SPA power supply to an earth ground will help. Put e.g. a 1/4 amp fuse in the line, to avoid a hazard in case the power supply develops a short. Don't try this unless you are sure that you know how to do it safely.

Why are you using Connect-Me at all? You should be able to completely eliminate the hum and noise by interfacing Skype with FreeSWITCH directly. See » ··· chs.html , or Google for other methods. Getting rid of the Connect-Me will also give you more capability. For example, you could be on a Skype call while your wife makes a landline call from another extension.

Why are you using Skype at all? If you are connecting to other Skype users and your Polycom is HD capable, eliminating the Connect-Me will allow you to enjoy a wideband connection, much higher quality than a normal telephone call. However, if you are making or receiving PSTN calls on Skype, IMO you'll get better quality (as well as better reliability and support) with a SIP provider. Depending on your usage pattern, that might cost a little more or less. What countries are you calling? Approximate monthly minutes? Do you have an incoming Skype number? About how much are you spending on Skype?

I haven't been able to get the skype module to work with freeswitch.
I think it has something to do with freeswitch or the skype module wanting full access to the audio devices on the server. But I haven't been able to confirm this.
This is a shared user server where several applications are utilized, including those applications that access the audio devices.
I'm finding other issues with the skype to spa3102 connection, such as caller id doesn't get forwarded, when a incoming caller leaves a voice mail message and hangs up, the line doesn't get hung up, leaving the land line open, most concerning is the audio quality is poor.
I've only had this box for a day so more testing is needed to determine if it can offer a suitable replacement to land line services.

The intention is to eliminate the land line service all together, Skype appears to offer the best prices. Right now I'm paying $50 a month for land line service that I rarely use. I'd like to eliminate this cost and use a pay as needed service like skype. There are other SIP providers but their cost is comparable to what I pay now.

reply to Stewart
Back to square 1, I found some reviews on the skype connect box and it has problems.
I'm returning this item in the next few days.

I'm going to try to run the freeswitch pbx or something else in a virtual machine and see if I can get skype functionality working.


reply to todd
I know nothing about Connect-Me, but I do have an SPA3102 and have had no trouble getting it to disconnect. When the caller hangs up, does the Connect-Me play a "disconnect tone"? If so, on the SPA's PSTN Line page, set Disconnect Tone to match. It's possible that the box interrupts loop current (CPC) or reverses polarity, in which case enable the corresponding option. If all else fails, you can set the SPA to disconnect when there is a specified period of silence.

For caller ID, confirm that you have a sufficient PSTN Answer Delay, and that the caller ID settings on the Regional page match what the Skype box sends.

However, IMO Skype (as a way to connect to the PSTN) is a poor value for the vast majority of users. If it seems to be a good deal for you, please post some details about where and how much you call, and how much you are spending with Skype.

You might try Google Voice (free to US and Canada; free incoming; see » ··· le_Voice ). I'm reasonably certain that the module doesn't depend on access to audio devices. For straightforward SIP (PAYG) service, look at Callcentric, Anveo,, or Localphone, listed IMO in decreasing order of price / quality / reliability / support. For heavy "unlimited" use, check Phonepower, VOIPo.

Allow me to clarify, when freeswitch and the spa3102 are connected w/o the connect me box, I don't have any issues. The issue present them selves when I put the connect me box in between the spa 3102 and the land line.

I've since given up on the idea of using the skype box as a means to convert ata (from the spa 3102) to skype's protocol.

I was hoping for a plug in and play approach since freeswitch is a bear to configure.
The plan was to replace the pstn line with the skype box and the pbx and spa-3102 wouldn't see any difference. But between audio issues and general functional issues, it's not going to work. I'll see if I can find a recent build and setup guide for freeswitch and the skype module.

Another thought would be to abandon skype and find a sip provider that doesn't cost a fortune to use...