In telecommunication, a data forwarder is a device that
  • (a) receives data from one data link and retransmits data representing the same information, using proper format and link protocols, to another data link.
and
  • (b) may forward data between
    • (a) links that are identical, i.e., TADIL B to TADIL B,
    • (b) links that are similar, i.e., TADIL A to TADIL B, or
    • (c) links that are dissimilar, i.e., TADIL A to TADIL J.

Source: from Federal Standard 1037C