June 2012
Where can I find a schematic or kit for a 16 button keypad encoder, without having to program a PIC? That's a regular telephone keypad plus A - D on the right side.
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Go to www.jameco.com and search for part number 32803. It is a DTMF Generator number TCM5089. Click on one of the three data sheet options to download and print the PDF.
Try searching on eBay for "DTMF encoder." I found more than a few there, but they aren't cheap.
DTMF ENCODER GENERATOR *** $34.00 *** 11 Days
www.ebay.com/itm/DTMF-ENCODER-GENERATOR-/400302522698?pt=LH_DefaultDomain_0&hash=item5d33e3c14a
HT9315C HOLTEK DTMF MULTIFUNCTION ENCODER CHIP *** $3.89 *** Only 1 day
www.ebay.com/itm/HT9315C-HOLTEK-DTMF-MULTIFUNTION-ENCODER-CHIP-/150826386913?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item231df405e1
DTMF ENCODER KIT WITH 16 KEY KEYPAD + TX KEYING OUTPUT *** $30.32 *** 10 days
www.ebay.com/itm/DTMF-Encoder-kit-with-16-key-Keypad-TX-keying-output-/270993370582?pt=LH_DefaultDomain_3&hash=item3f1876add6
While these will all probably be sold before you read this, you'll most likely find others. I'd ask the "Electrical_Components_Supplies_ET" place since they may have other chips.
The IC for DTMF encoding is a TP5089 from National, or a second source is TCM5089 from Texas Instruments.
It is available from Jameco (Jameco.com) as TP5089; their item #32803.
It's listed as available from stock on their website. You can also download datasheets from them to check before ordering.
