When I repaired OBD1 I used scopes to read what I want to read, instead of one interface you connect multiple equipment to the car (about 2 or 3) take a picture of them - its pretty much the same.
e.g. when looking for o2 sensor data on an S320 with M104 engine mercedes which has no OBD port - you either use the star scanner (usually the port is screwed up because the "lektrishann" tried to shove tools in it) or you use an oscilloscope, which provides perfect read.
same for old jap, euro or american obd-0 and 1 engines. the 2 interface is very good and I like it. one window solution. The one I love is the 38 pin port in mercedes benz.
p.s. - if you are working on older 100 series corollas then toyota have provided you with a diagnosis port, in that port you can force the ecu into test mode Te2 or read mode te1, measure rpm, measure o2 signal, check voltage, check fuel pump working. check Vf.
The VF is the most important signal here - it shows how much the ECU is handling the fuel trim. Do you use it or completely ignore it. Anyone who has worked in 4AGE BT engine knows its importance.