Omega A2400 - Manual (Page 6)

Getting Started 1-2
A2400 is to control the slave transmitter to allow multiple slave sites.
Figure 1.1 System Overview.
Leased Lines
This manual has been written with emphasis on radio modems. However,
the A2400’s may be used just as effectively with leased telephone lines.
Typically, leased lines do not have dial-up capability and some means of
addressing and multiplexing must be employed if multiple stations are used.
A2400’s may be used with leased line modems in an identical manner as
with radio modems.