d10control.pl:  Remote control of a DirecTV unit via the serial port
By Josh Wilmes (http://www.hitchhiker.org/dss)
Based on info from http://www.isd.net/mevenmo/audiovideo.html

Use the box_type "HD300" for LG LSS-3200A/Sony SAT-HD300/Hughes HTL-HD 
receivers.

Usage: ./d10control.pl command ...
Commands:
  box_type RCA|D10-100|D10-200|HD300  - select set top box type
  delay number    - wait for number seconds. Floating point is valid
  key string      - send remote key string.  See source for supported keys
  last_param      - execute last parameter on command line at current location
  number{-number} - change to specified channel-subchannel
  off             - turn box off
  on              - turn box on
  port string     - select port to send commands on, currently /dev/ttyS0
  setup_channel number - send on, channel change command and OSD off command
  version         - display program version

  baudrate number      - select serial port baudrate, currently 9600
  channel_change_type key|command - select channel change method
  get_channel          - print current channel
  get_datetime         - print date and time
  get_signal           - print signal strength
  get_info             - print information (HD300 only)
  enable_remote        - enable remote control (HD300 only)
  disable_remote       - disable remote control (HD300 only)
  hide                 - hide text, will also prevent info button from working
  retries number       - set maximum number of retries on error
  set_system_datetime  - set PC clock from box.  ntp is more accurate
  text string          - display string on screen, "" to clear
  verbose|quiet        - select how much information printed

Mythtv command for normal RCA box: directv.pl setup_channel
Complex Mythtv command for D10-200 box doing same as setup_channel:
   directv.pl box_type D10-200 on last_param delay .2 key exit
Mythtv adds channel number at end of command