HDLC104 Highlights:

  4-channel concurrent operation
  Individually configurable for HDLC / Asynchronous operation
  Rugged, Locking I/O connectors
  2000Vrms Galvanic Isolation for each port
  Linux & Windows drivers available
  Extended temperature operation (-40 to +85 deg C)
  PC/104 form factor
  Single +5 power supply

The HDLC104 has been designed for demanding transportation and industrial applications.