Item details DIY Keypad DTMF Tone Generator Assembled and tested with Keypad - included: Jumper wires, Schematics. - This kit include the 4x4 Keypad. - Kit output is CMOS logic , please don't forget to include ground wire when interfacing to other circuits . - Include 10nF coupling capacitor when interfacing to cell phones , and use coupling transformer or/and Zener diodes when hooking up to regular home phone ( land line ) . - Here is is the link for the DTMF datasheet : Quantity - 1 KIT Product Description: Additional Data - Click on the datasheet button below for full technical specifications: - Don't forget to sign up for our newsletter for special discounts and sales Shipping Policy Dear Customer, -When you want to buy other listings and save on shipping you must remember to pay for them only after you are done buying all the listings, I recommend using " Add to cart " instead of the "Buy it now" -will assemble a discounted invoice and save you the shipping cost. In case that it does not happen don't pay yet, just use "contact seller" and say "please send me an invoice," I will calculate the discount for you, then will send you a new PayPal invoice. -I rely to calculate totals automatically so, always contact me to get refund if we overcharge on shipping more then $3.35+(number of additional items)x$0.10. -We are interested seeing you again , so when package arrives let me know if you are not 100% happy with the purchase , I can surely help to resolve any issues , by offering great solutions , exchange or refund , I will try to answer any questions within 5 hours or less Hope to see you again ,Sincerely Sean Other Items In our store: