Hi group,

I need an FCC approved interface to the phone to be used for DTMF. And cheap. I want to connect a DTMF decoder to a PIC.

Any ideas??

 

That would be mostly for production of a device that will be connected to the telco lines. Prepare to spend blood sweat and tears and delays and paperwork and application fees.

What you want is called DAA Direct Access Arrangement. Do a search under those terms and several chipsets will show up from several vendors whose products are pre-approved and accepted by the FCC.

I have done several projects for personal use without the approval. Knowing the regulations, compliance is not complex at all. Actually very simple. The FCC approval is the hurdle. All they want is make very sure the item connected to telco lines won't ever harm their equipment.

The old Motorola communications data book is very explanatory, if you can find one. Also Silicon Systems data books; and several others. There has to be something in the net, by searching as told above.