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DSR / DTR and solder pads - Printable Version

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DSR / DTR and solder pads - Baldrick - 01-24-2018

Hi there.

I am confused by the passage on pages 19 and 20 of the manual.

There are two scenarios shown plus the default one as shipped.
I would like to see all the possible permutations of cuts and bridges, because what's there is unclear to me.

DSR and DTR are normally two separate RS232 signals, as are RTS and CTS.  Sometimes combinations of the two are joined together (as in the Hayes 56K Sportster supplied with an Apple DIN-to DB25 cable that joins DTR with RTS).

I am trying to figure out right now how to use the Apple IIc+'s hamstrung serial port (with only DTR, DSR, TX, RX, and GND signals available) to achieve both 4800 baud and higher (WIMODEM232 is not responding above 2400 baud as delivered) and attempt to get old BBS software to talk nice with the modem - so far I have achieved a remote connection, but no hangup.  As you can see, there is no CD pin.  Presumably, the modem would have to drop DTR to achieve a hangup condition?

[Image: IIC+serial.png]

If there are four separate signals, DTR, DSR, CTS and RTS available on the WIMODEM232 and only DTR and DSR on the computer's serial port, how would I go about configuring the bridges/cuts so that I can achieve some sort of handshaking?


RE: DSR / DTR and solder pads - admin - 01-24-2018

You shouldn't need any handshaking until you reach 9600 baud (at least that is my experience with all of the systems I have). I know that people are using 9600 baud with their Apple IIc and IIgs systems with just the standard cable. You can NOT use a null modem cable. You have to use a standard DTE->DCE (modem) cable.

If you want to use DTR/DSR in place of RTS/CTS, cut all three jumpers and solder exactly as shown in the manual.

What terminal program are you using? It's likely that you have something set incorrectly.


RE: DSR / DTR and solder pads - Baldrick - 01-24-2018

I'm using Proterm 1.9.
But what do you mean when you say "standard cable"? Standard as in one like mine that ties the DTR to RTS? Does this cause issues with the Wimodem232? It seems to work fine until 2400 baud, but not 4800 or 9600.

I may need to make a new serial cable - one that doesn't tie those to signals together.
Or maybe you can suggest a pinout based on the signals in the diagram above - which is common to the Apple GS so far as I know.


RE: DSR / DTR and solder pads - admin - 01-24-2018

Having DTR tied to DSR is normal. The computer brings DTR high and expects DSR to go high when the modem is ready. What problem are you having with higher baud rates? If the cable works at 2400 baud, then it works at all baud rates.

Any reason you are using ProTerm 1.9 instead of the latest v3.1?


RE: DSR / DTR and solder pads - Baldrick - 01-24-2018

(01-24-2018, 02:15 PM)admin Wrote: Having DTR tied to DSR is normal.  The computer brings DTR high and expects DSR to go high when the modem is ready.  What problem are you having with higher baud rates?  If the cable works at 2400 baud, then it works at all baud rates.

Any reason you are using ProTerm 1.9 instead of the latest v3.1?

Tried it with ProTerm 3.1.  I can now achieve 9600 baud.  Must be something weird about ProTerm 1.9.
Thanks.


RE: DSR / DTR and solder pads - admin - 01-24-2018

Yeah, I had heard that older versions didn't actually support higher than 2400 baud.