With Data Modem To Transmitters - ASCOM T942C System Installation

System Installation
Ascom Paging System
.
A-bus
Figure 2. System solution: 2-way data communication.
2.3

With Data Modem to Transmitters

Data modem introduces delay in the transmitter signal. Transmitter signals "in the air" will
differ and cause distortion in areas of overlapping coverage. A basic rule in planning an
installation is to delay the signals to transmitters equally.
The transmitter code on the D-bus is always generated by the Central Unit. Be sure that
the same number of modem-pairs are used between the Central Unit and each Terminal
transmitter. Several Terminal transmitters can be connected to one Data modem if the
location is suitable. Synchronize the data modems for the D-bus, see the figure below:
Figure 3. Private lines with data modem.
Reference
Module
Control
A-bus
D-bus
System bus to
other units
10 October 2013 / Ver. D
Central Reference
Unit Module
R-line
FL-bus
to central site
D-bus
Central
Data Data
Unit
Modem Modem
Synchronizing
Receiver
Interface
R-line
to terminal site
FL-bus
D-bus
Terminal
Fixed
Transmitter
Receiver
Data Data Receiver
Modem
Modem Interface
D-bus
R-line
D-bus
FL-bus
Delayed buses
A-bus
direct to terminal site
D-bus
Buses via modem
at terminal site
TD 90227GB
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