Diagnose DTR/DSR and RTS/CTS issues

TS-DOS and TEENY depend upon at least DSR to be high during operation. TS-DOS may also depend on CTS being high during operation.

If DSR is low, then these programs will refuse to operate.

NADSBox loops back the laptop's DTR to DSR. Also, it loops back RTS to CTS.

So, if your laptop's DTR, DSR, RTS and CTS lines are working, you should have no issue communicating with NADSBox.

This program will let you detect if these outputs and inputs are working. If the values change depending on whether NADSBox is connected, then your flow control lines are working properly. If one or both do not change, then there is a problem with your flow control lines are outbound or inbound for the relevant pair (DTR+DSR, RTS+CTS).

Note that this code is for the NEC 8201A and 8300.

You must change the "COM:9N81NN" to "COM:98N1E" for the Model 100.

10 CLS
20 DEFINT D
30 OPEN"COM:9N81NN" FOR INPUT AS 1
40 OUT 186, (INP(186) AND 63)
50 DS=INP(187)
60 DR=(DS/32)AND1
70 DC=(DS/16)AND1
80 LOCATE1,3:PRINT"DSR: ";DR
90 LOCATE1,4:PRINT"CTS: ";DC
100 GOTO 50