Tyco Electronics MM102014V1 - Manual (Page 10)

MM102014V1, Rev. G
3 PRODUCT DESCRIPTION
The M-803 digital mobile radio is a hardware component of the OpenSky® network, an integrated voice
and data communications system that delivers end-to-end digital transmissions over a single wireless
network to the dash-mounted or trunk-mounted radio receiver. There are two principle operating modes
for the radio.
• OpenSky Trunked Protocol (OTP)
• Optional OpenSky Conventional FM, (OCF)
OCF allows operation on conventional analog channels with Continuous Tone Coded Squelch System
(CTCSS). OCF also allows operation on P25 conventional digital channels using the digital P25 CAI
(Common Air Interface).
The M-803 is intended to operate in a mobile environment, typically a motor vehicle. The radio operates
over both the Specialized Mobile Radio (SMR) and National Public Safety Planning Advisory Committee
(NPSPAC) frequency bands. These bands provide more than 840 possible channels spread over the 806-
824 MHz transmit and 851-869 MHz receive bands. The M-803 operates half-duplex with a 15W
(typical) transmit output power. Optional full-duplex operation is also available.
The M803 is available in four hardware configurations, three of which are further defined for data
operation as half- or full-duplex:
• Dash mount with built-in control head. Additional remote control heads can be added (half- or full-
duplex).
• Trunk mount with a single or multiple remote control heads (half- or full-duplex).
• Data only – No control head (half- or full-duplex, PC required).
• V-TAC Full Duplex Vehicle Repeater with a one or more remote control heads.
The M-803 uses Time Division Multiple Access (TDMA) technology to allow multiple users to share a
single RF channel. In addition, a single RF channel can support simultaneous digital voice and data
communications. The V-TAC takes advantage of OpenSky’s TDMA ability to minimize interference
between its local and network radio links when operating in an Extended Coverage mode (XCOV or
XCOV-TG), an undesirable characteristic of many traditional vehicular repeater systems.
The M-803 provides integrated voice and data services. Voice operation is provided using a microphone
and speaker included in the radio installation kit. For data transfers, the M-803 is constructed with an
industry-standard RS-232 interface serial port for connecting an optional laptop PC.
A PC, not included with the M-803, provides network connectivity through the standard serial
(DTE-type) interface.
The M-803 is a “soft” radio. Its functions are determined by the software applications installed.
The optional GPS tracking devices embedded in M-803 radios can provide quick and accurate positional
information to a connected laptop locally in the vehicle. GPS can also provide positional information over
the radio link, if configured to do so.
Unlike most dispatch radio systems, however, an active transmission can be pre-empted by a dispatcher
or supervisor. This results in the transmitting radio instantly switching to receive the “priority” in-bound
call. Normal operation can be resumed once the in-bound call is concluded. This feature is particularly
useful for V-TAC users operating as a scene commander.
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