Dual PCs to ZX circuit - viable?

[stevech]

would this circuit permit two PCs' serial ports to share access to a ZX module?

By arrangement, the two PCs and the users would coordinate their access actions.

[dkinzer]

My conjecture is that it would work assuming, as you have suggested, that the PC will not be transmitting at the same time.

If you are using a ZX-24 or ZX-24a, you may need to add a resistor to ground (10K or so) on the receive input (pin 2) since the current design does not have a pulldown.