Thanks Astronerd.
Everything works great immediately after I use Serial Port Assistant, until I restart the RPi, then I'm unable to connect. However, if I pull out all the devices, delete all the Serial Port Assistant entries and reallocate then I working again until the next restart.

I'm using a EQmod cable directly to the mount, rather than via the handset. Not sure if it's FTDI or Prolific, or how to tell the difference.

lsusb returns the following

Bus 001 Device 004: ID 10c4:ea60 Cygnal Integrated Products, Inc. CP210x UART Bridge / myAVR mySmartUSB light
Bus 001 Device 006: ID 1546:01a7 U-Blox AG
Bus 001 Device 005: ID 0471:0329 Philips (or NXP) SPC 900NC PC Camera / ORITE CCD Webcam(PC370R)
Bus 001 Device 007: ID 0424:7800 Standard Microsystems Corp.
Bus 001 Device 003: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 002: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

The first entry is the USB-serial adapter connected to the mount.

Thanks, Chris

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