MM-007024-001
11
3 INTRODUCTION
3.1 GENERAL
DESCRIPTION
The M7200 series mobile radios are high-performance full-duplex dual-band digital mobile radios. These
radios can operate on 700 MHz and 800 MHz OpenSky trunked radio networks using the OpenSky
Trunking Protocol (OTP). In the future, the radio will also operate on 800 MHz Enhanced Digital Access
Communications System (EDACS) trunked radio networks, and 800 MHz APCO Project 25 phase I
compliant Common Air Interface (P25 CAI) trunked radio networks. Other future operating modes
include talk-around communications in accordance the APCO Project 25 phase I standard, and
conventional FM repeater-based and FM talk-around voice communications in accordance with the
TIA/EIA-603 conventional land-mobile radio standard.
NOTE
The initial release of this radio only supports operations on 700 MHz and 800 MHz
OpenSky trunked radio networks. Later releases of the radio will add other modes to
support other trunked radio networks, and conventional FM repeater-based and FM
talk-around voice communication modes.
The radio has two models:
•
M7250 — Trunk-Mount Full-Duplex Mobile Radio with CH-103 or CH-103PA Control Head
•
M7270 — Trunk-Mount Full-Duplex Mobile Radio with CH-721 Control Head. As of the
publication of this manual, this combination is not available.
This manual only covers the installation of the M7250 model mobile radio.
The M7250 model mobile radio is designed to operate in a mobile environment, typically within a motor
vehicle. It must be connected to an external transmit/receive antenna such as one mounted to the vehicle’s
rooftop or trunk lid. In high-power half-duplex mode, the radio’s 800 MHz RF transmit output power is
rated at 15 watts minimum. The high-power limit for 700 MHz interoperability channels operations is
300 milliwatts maximum. This high-power limit guarantees that the 2-watt ERP (effective radiated
power) limit of the 700 MHz interoperability narrowband channels is not exceeded when the radio is
connected to a 6 dB gain antenna. Several different types of external-mount antennas are approved and
available for use with the radio, as listed in Table 1-1 and Table 4-2.
The radio is designed for remote mounting in a motor vehicle’s trunk, or some other preferably
unoccupied section in a vehicle, such as a fire truck’s equipment shelf. It is remotely controlled by one or
more control heads connected to it via a 3-wire Controller Area Network (CAN) link cable. Between the
radio and control head(s), the CAN link carries digitized microphone and speaker audio, controlling data
such as button presses and radio messages, and user data such as that for a mobile data terminal connected
to serial port of the radio or control head. For proper operation, the CAN link must be terminated
appropriately on each end.
Control heads which may be utilized with the radio include the standard CH-103 and the siren/public
address CH-103PA control head. The CH-103PA can interface to an optional Federal Signal Electronic
siren/light control system for broadcasting via a public address (PA) speaker. In multiple control head
installations, control heads are interconnected to the mobile radio in a series (daisy-chain) fashion via
CAN link cables. Other control head models are planned in the future.
The radio must be powered by an ex13.6-volt (nominal) DC power source. In mobile applications,
the motor vehicle’s electrical system is the source of DC power. The control head(s) connected to the
radio is also powered by the same DC power source, but separately fused. When the control head is
powered-up by the operator, it “wakes up” the radio by transmitting data to the radio via the CAN link.