Figure 1-3 ltr-net system components – Viking 242-2009-632 User Manual
Page 25
 
INTRODUCTION AND OPERATION
1-9
March 1999
Part No. 001-2009-600
Repeater Connection To Switch
The repeaters can be located at the same Locality
as the Switch or they may be located at a Locality that 
is many miles from the Switch. A voice and data link 
is required between the repeaters and Switch. This 
link can be a direct connection, phone lines, micro-
wave, RF transceiver, fiber optic, or some other type 
of link. This link is connected to the repeater terminal 
block on the back of the repeater.
The voice link routes transceiver voice to and
from the Switch. The voice must be routed to the 
Switch when a call involves a dispatcher, telephone 
interconnect, or another RF channel or LTR-Net sys-
tem. If the call is a mobile-to-mobile call on the same 
RF channel, the voice is simply repeated by the 
repeater (it is also routed to the Switch but is not con-
nected to anything). The voice path input/output port 
interfaces with a standard 4-wire, 600 ohm phone line.
The data link allows the Switch to control the
repeater. With mobile-to-repeater calls, the data fed to 
the Switch is used to determine what routing is 
required for the call. On Switch-to-mobile calls, the 
data fed to the repeater allows the Switch to operate 
the repeater like a base station.
There are three different types of links that can be
selected for the data path between each repeater and 
the Switch. The MPC is programmed for the type of 
link used (see Section 1.11). 
•
A 4-Wire voice-grade link can be used that is similar 
to the audio link. The data is then sent as tones using 
FSK modulation.
•
RS-232 serial inputs and outputs are available for 
direct connection or connection to a link that accepts 
RS-232 data.
•
Data can be modulated as in ’1’ and then sent over 
the voice path using a Blank and Burst technique. 
Only one 4-wire link is then needed between each 
repeater and the Switch.
Figure 1-3 LTR-Net SYSTEM COMPONENTS
MOBILE TRANSCEIVER
MOBILE TRANSCEIVER
MOBILE TRANSCEIVER
CONVENTIONAL
LTR
LTR-Net
LTR-Net REPEATERS
(UP TO 20 PER SWITCH)
AUDIO AND
DATA LINK
AUDIO AND
DATA LINK
AUDIO AND
DATA LINK
SYSTEM and SUBSCRIBER MANAGER (SSM)
PUBLIC SWITCHED
TELEPHONE NETWORK
(PSTN) OR PABX
OTHER SWITCHES
AND SYSTEMS
TIM
WAM/SNM
CIM
CIM
CCM
NetNIM
3000 SERIES SWITCH