Cybiko (9-4) Cable

Signal	Computer 9 PIN D-SUB FEMALE	Cybiko 4 PIN FEMALE
Transmit Data	3	2
Receive Data	2	1
Request to Send	7	3
Clear to Send	8
Data Set Ready	6
System Ground	5	4
Carrier Detect	1
Data Terminal Ready	4
Ring Indicator	9

Note: Testing for ground on the last pin is the safest way to ensure you have the pinout correct. My tests seem to show that the ground signal is on the pin closest to the power connector. The cable has an arrow pointing to the pin which is inserted furthest from the power conector. This seems to match with the schematic.

See also:

• http://martybugs.net/electronics/tempsensor/hardware.cgi a very simple and low cost serial temperature sensor.