Paul,
If the blinking red LEDs do not come on I would guess the modem is not completing its POC and is broken. Maybe one of the
SSB installers (Dockside
Radio, Bill Trayvors, etc.) can test it and maybe
repair it.
On the chance it is actually working try checking the Ignore CTS option in Airmail. There can sometimes be a timing problem between Airmail and the modem. This fixed a problem for me. Link to a
screen capture of the option under Airmail below.
John