I'm not sure exactly what you are talking about, but it sounds like you might want to take a look here http://www.compsys1.com/workbench/On...3_adapter.html
you should be able to use one of these adapters (i would recommend A232DBH ). Make sure you know if you are ordering the assembled board, or an unassembled kit.
Your talking about the Clifford Alarm units, right? Well, my question is this, are you talking about the version that has PC software for program or the bitwriter units? Cause if the alarm is bitwriter compatible, then you would have to write your own programming software for the alarm.
The diagram is the exact copy of it, so just follow the guide and make your clone from it.
I cant seems to work out what is the part number for the regulator. It say something like LM293 which is a wrong part number. That regulator should be equivalent to the 78L05 +5V regulator as the SP232ACN requires a 5V supply.
The SP232ACN is equivalent to MAX232CPE, if you do need to use that part then you must change the capacitor C4,C5,C12 and C13 to 1uF. I have no idea why the C13 is rated at 50V. 25V rating for all the capacitor should be fine. Just follow the standard MAX232CPE circuit.
The optional power is not really needed so R2 and the jack socket can go. The Clifford alarm can provide the supply.
The cliffnet female connector is viewed from the front with the champered edge on the top. That is the connector on the cliffnet adapter cable as shown on the pics. So make sure you dont get confused with the Clifford alarm unit itself. Same goes for the DB9 female connector.
If in doubt use a multimeter on the Clifford alarm to verify the connections. You should see a GROUND, +V and I/O. I dont know how much the +V should be as I no longer have that type of alarm but it should be greater than 5V.
Just be warned, I have never built this circuit, I only drew what I saw from the circuitboard so there could well be some errors. I shouldnt think so but you never know.
Thats it. Good luck and let us know how you get on.