Codan Radio MT-4R - Manual (Page 16)

UG-001 Daniels MT-4R and MT-4D Radio Systems
www.danelec.com
Chapter 2: Technical Information 8
User
Guide
LVDS SERIAL DATA
Daniels MT-4R and MT-4D Repeater modules use Low Voltage
Differential Signaling (LVDS) serial data to communicate between
receiver, controller and transmitter modules. MT-4D Base modules
do not use LVDS serial data.
A conventional analog repeater uses analog audio to communicate
between the different modules. Daniels P25 radio systems use serial
data between modules to allow for a completely transparent digital
path between the modules. This means that all digital information is
passed through the repeater system quickly and completely intact.
When a Daniels P25 Receiver receives a P25 digital transmission,
the receiver samples the incoming information and then creates
an LVDS serial data stream (of 257.8 kbps) that contains the same
information as the Common Air Interface (with some overhead data).
When a Daniels P25 Receiver receives an analog transmission, the
receiver samples the incoming information and then creates a serial
data stream (of 257.8 kbps) of the analog information. The incoming
frequency and deviation is converted to serial data through an A/D
converter. The transmitter uses this information to recreate the P25
digital or analog transmission.
DANIELS P25 DATA PACKET REPEATING
(OTAR, GPS, ETC.)
The P25 Common Air Interface (over the air signaling) supports
Voice Messages and Data Packet Units (confi rmed or unconfi rmed
data messages). Data Packet Units support Over The Air Rekeying
(for encrypted systems), GPS position information, and other data
applications.
Daniels P25 MT-4D repeater modules are capable of repeating the
P25 Data Packet Units. The MT-4D receiver and transmitter modules
must have fi rmware version 2.0 or higher to properly repeat Data
Packet Units. MT-4R modules are not capable of repeating Data
Packet Units.