Radio Shack 49-452 Digital Keypad w/PIC

Radio Shack 49-452 Digital Keypad w/PIC

Post by Dwain Couf » Mon, 17 Feb 1997 04:00:00

Slightly off topic:

Has anyone interfaced a PIC chip to a Radio Shack Digital Keypad model
# 49-452?  The back of the keypad has +/- power connections, 4
possible address settings, and a Serial Data 1 and 2.  Is this true
serial data?  Which is input and which is output?  Or is the data flow

I want to interface this keypad with a PIC 16c84 to control a home
alarm system.  It seems like it would be easier to use this keypad
than to create one.

When powered up, the keypad signals that it's connection with the
alarm consule has been severed.....and it won't allow you to do
anything.  So, I also need to know what signal needs to be sent to the
keypad to allow it to function.

Any help is greatly appreciated.



1. Anyone hacked a RS 49-452 keypad?

        The subject line should say it all but...

Has any one hacked the Radio Shack 49-452 digital keypad
in an attempt to use it with other systems?

In particular I would like to build an alarm with multiuser
multipoint entry system. This cute little keypad is fairly
inexpensive and is reported to use rs232 communication.

From dissecting one, not much can be found except a few discreet
parts and a tandy ~18 pin surface mt part.

Applying power & observing with a scope I was not able to
determine if anything was being sent over the serial port.
Is this older current loop technology?

Above & beyond determining baud & bits, what is the data

Also, does anyone know if it is difficult to obtain the
RS service manuals. Their web page lists them in the parts
list for each product.

(I just received mail from RS that at least the raw information
  on the transfer protocol was not available (surprise!)).


Peter Mooers

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