RS232 Full Duplex to Half Duplex

The port itself is not the problem - it just sends and receives data. Full duplex and half duplex refer to terminal modes. In full duplex the characters typed must be echoed back by the external device. In half duplex, each character is echoed locally and then transmitted.

I'm not sure that there is such a thing as RS-232 half-duplex.

Still, I'm sure there is some kind of solution for your problem, but it would help to know more about the half-duplex device. What does it do? Are there any control signals which would tell you whether it is transmitting or receiving? When it is not transmitting, does it go high impedance?

Do you have a link or a datasheet or something?

--Mac

I stand (somewhat) corrected. Half-duplex can refer either to a communications circuit that can only transfer data one way at any one time, or to a terminal communication requiring local echoing - even when the hardware is itself full-duplex.

Half-duplex vs. full-duplex isn't a hardware issue - it's how the software coordinates what's coming in and going out. The most notable difference I can think of is when you want to run a dumb terminal half- duplex, you turn on local echo.

So ignore the remote echo, and you've got half-duplex. Maybe turn local echo on in the one that's full-d now - that'll make it half-d.

Cheers! Rich

Duplex means communication can go in both directions. 'Full' when send/receive can occur simultaneously, 'Half' when this is not possible, for whatever reason.

Local echo on a terminal is only a feature to help the operator a bit if the receiving end does not process/echo it back. Full/Half duplex is not restricted to terminals or characters being typed. It can be any kind of data, human readable or not.

That 'whatever reason' being commonly a bitbanging lash up involving a PIC.

Paul Burke

use the hand shaking lines. CTS, RTS DSR etc..