Summary: Digitrax employed an Alias Roster, a database in the DCS100 Command Station, which permitted a 4-digit address to be an alias for a 2-digit address.
Aliasing allowed the user to assign an Extended Address to early multifunction decoders which only supported a Primary Address. The DT100 throttle could display an aliased address, called the Expanded Address Mode. The DT400 throttle supplied with later starter sets does not support this feature.
This mode was controlled using Option Switch #25 in the DCS100 Command Station. The DCS100 created and maintained a database which matched a 4-digit address to a 2-digit address. This database would be preserved when the power was shut off.
This feature is obsolete, included here for historical reference.