Category: Amateur Radio

Per the socat man page:  “Socat … establishes two bidirectional byte streams and transfers data between them”. Using it to connect minicom to the HP Z3801 (PDF user manual) GPS receiver’s serial port on the PS410 serial server goes like this:

socat pty,link=/tmp/z3801 tcp:192.168.1.40:7003 &

The 7003 designates the network port corresponding to serial port 3 on the PS410. The PS410 lets you give its ports any numbers you like, but that way lies madness.

You may want to run socat in a separate terminal window for easy monitoring (use -d -d for more details) and restarting. The PS410 closes all its network connections when updating any configuration values, pushing any ongoing conversations off the rails. Of course, one doesn’t update the configuration very often after getting it right.

It produces a device with permissions just for you:

lrwxrwxrwx 1 ed ed 10 Mar 17 18:45 z3801 -> /dev/pts/2

Whereupon you aim minicom (or whatever you like) at the device:

minicom -D /tmp/z3801

And It Just Works.

The PS410 serial port configuration:

The default Z3801 serial port setup seems to be 19200, 7 data, odd parity. I vaguely recall some serial port hackage a long time ago, with the details buried in my paper (!) notes.

Leaving the Inter Character Timeout at the default 0 creates a blizzard of network activity. Setting it to 10 ms produces slight delays during the full-screen (on an 80 character x 24 line green screen monitor, anyway) status display:

I inadvertently turned off the UPS powering the thing and the double-oven clock oscillator takes days to restabilize; the Holdover Uncertainty has been dropping slowly ever since.

Verily, it is written that a man with two clocks never knows what time it is. When one of them is a Z3801, the man has no doubt which clock is correct.