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 has the feature that it 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, TS-DOS should work fine with NADSBox. If TS-DOS or TEENY refuse to operate, you may have an issue with one or more of these signals.

This program detects 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 either outbound or inbound for the relevant pair (DTR+DSR, RTS+CTS).

Note that it makes no difference whether NADSBox is on or off during the diagnostic. Also, it assumes the default in that RTS is looped back to CTS (this is configurable by the user through a jumper in NADSBox... see the manual).

NEC 8201A, NEC 8300 Version

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

Model 100 Version

(untested... let me know if you try this before I do)

10 CLS
20 DEFINT D
30 OPEN"COM:98N1E" 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 PRINT@1,"DSR: ";DR
90 PRINT@41"CTS: ";DC
100 GOTO 50