Credit Card Processing over VoIP

I am trying to use a TDM400P with a Credit Card Processor. It is a basic Analog Machine that is directly connected to my FXS Module in the TDM400P. Can someone give me some guidance on troubleshooting the connection problems it is having. I can get it to dial out, but it the sends and recieves and eventually asks me to retry. Is there echo or noise issues that I need to overcome? How would I check?

Is the call going out over VOIP or an fxo on the tdm400

The dredit card machine is basically a modem and modems and VOIP doesnt mix well see link

Thanks rusty,
I am starting to realize now that I am still going to have to purchase an analog line. The worst part is that I have to return my Digium card, cancel my VoIP service and call it a loss. I have to have a reliable phone and credit card processing capabilities. And I now have to pay much more for it.
-Scott :frowning:

you don’t need to return the TDM card, just get an FXO module for it.


It should work. I have a couple customers with Credit card machines conected to Grandstream ATAs and they are working with no problems. Just make sure you are sing G711. And I have tested it over Voip lines and that also works as long as you dont do any transcoding


What is transcoding and how can I be sure that I have it off.
See, I only need the ATA for my credit card machines. I’ll be fine using soft phones for my voice calls. How would I go about configuring the TDM400P for the credit card machine???

Its nothing but a myth when people say modems do not work with VoIP “Totally untrue” says I. All you need is an ATA like the Linksys/Sipura SPA1001, SPA 2002 and up (supports T.38 fax, and via G.711), etc, go into the GUI, configure the SIP parameters and connect your modem device such as a credit card machine, fax, etc and watch it connect. I have different voip providers and I send and receive faxes effortlessly over my voip ATA, and fax machines use modems. The ATA (and modem) basicly do(es) the digital<–>analog conversion on both the sending and receiving ends. The only thing is you will need to look into encrypting the credit card info being sent over the internet in this process, I wouldn’t want that to be my card info being exposed online, neither will you.

You may also want to check out CISP requirements for secure CC transactions. If you are sending raw credit card data over the internet, you may be in violation. … /cisp.html