Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

converting telephone keypad display to normal keypad display

Status
Not open for further replies.

theused69

New Member
I found this schematic from this site

telephone number display circuit diagram

And it seems to have just what I need: a keypad display without using microcontrollers. Now I need only the keypad display. My basic idea is to remove the whole CM8870PI and the logic gates near it, put push button switches representing digits 0-9, and then use a 74- BCD encoder, and hook it to the ABCD and that's it. I just need to clarify some questions regarding the conversion process

1) Will my idea work?
2) Does pin 15 of the CM8870PI hold some value? If it does, can I convert it?
3) I can't see IC11 and IC12. What is the author talking about?
4) Are there any 74xx equivalents for CD4017BE, CD4508 and CD4511? I think 7447 can replace CD4511, but I'm not sure

There are still many other questions that I might ask, but this just for now. Any help would be appreciated. Thanks :D
 

Attachments

  • 11(2).gif
    11(2).gif
    45.2 KB · Views: 247
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top