Vey wrote:
Vey wrote:
When a program asserts these to go high, the voltage is supposed to
increase to more than +3VDC, right?

Looking at my multimeter, mine aren't doing anything,

Well, I measured again. I see +0.03VDC and -0.03VDC on RTS Hi/Lo (pin4)
and -0.001VDC and -0.02VDC RTS Hi/Lo (pin7).

So maybe that explains the loopback test passing, but that's no where
near 3 volts and the literature says those readings are considered to be
"transitory" voltage.

Are you measuring the output pins at the serial connector without a
load such as a modem on them. Remember a wrap block places the load of
a receiver onto the transmitter. Take a bare jumper and wire DTR to
DSR and look at the voltage level. You can do the same with RTS to
CTS. +3VDC is too low. I have seen good ones run anywhere from + or -
6volts to + or - 15 depending on the device.

Van Gardner