The One Touch RS-232 Adapter cable

Here is the circuit for the adapter that has been successfully used for data transmission between One Touch glucometer and a personal computer. This one is designed to fit inside D 25 connector case but if you leave the circuit board out the circuit can be fitted inside a D 9 connector case.

The circuit is designed by Matti Eskola 1995. Even though the circuit has been carefully tested, no warranties can be granted. You'll need some experience in electronics before you can start. All information presented here is as is, no warranties and so on...

Parts list
Component Value
R1,R2 22k
R3 68k
R4 47k
C1 1uF tant. 
C2 10uF tant.
T1 BC548C
T2 BC558C
D1,D2 1N4148
REG1 78L05

Another circuit utilizing the max232 IC is available at

This page is maintained by Kirmo Uusitalo.