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Sending a file to Com1 using DOS 6.22

By regular guy ·
I am trying to send a DOS text file to a device attached to the serial port on a DOS 6.22 PC.
The attached device basically uses only the send and receive data lines along with the ground line-no CTS, RTS, etc... DOS sees the device as unavailable because it is looking for some kind of handshake. In NT, 2000 this can be accomplished because you can tell the advaced versions of Command to ignor handshakes, but I have to use DOS 6.22 and the Mode command is limited.....??????

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Sending a file to Com1 using DOS 6.22

by Ann777 In reply to Sending a file to Com1 us ...

There's a section in the below link that describes a cable modification that may work in your situtaion (it's about 75% of the entire page down -- also the site is black background w/white text).

http://www.algonet.se/~dennisgr/z88-dark.htmIt begins:
DOS by itself does NOT use Xon/Xoff and it does not use hardware flow control when receiving but it does when sending.

The Z88 hardware flow control is always active so when trying to send, the Z88 never receives a positive voltage on pin 5 CTS to be able to send.
One useful source for a positive voltage is the PC pin 20 DTR instead of the PC-Link connection to pin 4 RTS. The connections would then be exactly the ones recommended in the Z88 User Manual for connecting to a printer, apart from the fact that the printer needs a male connector. A printer cable and a gender changer will do the trick.

No flow control is then active when sending to the PC. I only guess it is OK as long as the received data fit in the available RAM and must not be written to disk and interrupting the possibility to correctly receive data.

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Sending a file to Com1 using DOS 6.22

by regular guy In reply to Sending a file to Com1 us ...

This response solved the problem (with a minor ajustment). Pin 20(DTR) needs to be tied to pin 6(DSR), pin 8(DCD), as well as pin 5(CTS) in order to 'trick' DOS. Thanks.

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Sending a file to Com1 using DOS 6.22

by maxwell edison In reply to Sending a file to Com1 us ...

You don't mention the DOS application (if any) you're using, but if I recall correctly, one can simply use a DOS command to send a file (especially a text file) to any device.

For example, from the DOS command prompt:

copy name.txt>com1

or
type name.txt>com1

or

print name.txt>com1

One or all of those should work to send your text file to the device attached to COM1. You don't say what device is attached, but if it's a printing device, the file should print.

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Sending a file to Com1 using DOS 6.22

by regular guy In reply to Sending a file to Com1 us ...

Thanks for your comment but, believe me, I have tried all that. The problem lies in the flow control that DOS is looking for, if DOS is not getting a CTS, it believes the device is not ready.

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Sending a file to Com1 using DOS 6.22

by regular guy In reply to Sending a file to Com1 us ...

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