Calypso modem usage
===================

On the Openmoko Freerunner phone, the Calypso modem is presented by
the kernel as serial device /dev/ttySAC0.  To allow oFono to
autodetect and use this, a simple udev rule is needed:

KERNEL=="ttySAC0", ENV{OFONO_DRIVER}="calypso"

You can put this in any file in /lib/udev/rules.d.  A logical choice
is the "55-openmoko-gta01-gta02.rules" file, if it exists in your
Freerunner distribution.

With this rule in place:

- oFono will detect the Calypso modem when it starts up, and the
  `list-modems' test script will show this, but will not power it up

- the `enable-modem' test script can be used to power it up

- a subsequent `list-modems' will show lots of information, including
  network registration.