i think its a obd1 p28 but with obd2 socket already converted by hondata,so you dont need obd2 converter harness.can't find the website that sell it but,N1 racing in sunway have these.
since you already running obd1 wiring, i guess you are currently using an obd1 ecu.in my opinion, you can buy s300 hondata and put it in your current ecu. my mech once quoted me around RM1800 for the s300+installation.