The VRM 850 is a data-only, mobile radio modem built on the MCS 2000 radio platform. Voice communication is not supported. The VRM 850 provides connectivity between a vehicle-mounted data terminal and the system’s host computer through the Private DataTAC radio network. The connected terminal must use either the Transparent mode (AT command set) or Native mode (Native Command Language) interface. The VRM 850 is qualified to meet MILITARY STANDARD 810 D & E specifications for shock, vibration, rain, dust and salt environments. The unit may be dash or remote mounted and requires a 12V dc negative ground power source. An antenna is not included and must be ordered separately. The antenna connector is a mini-UHF female type.
The Private DataTAC Solution
The VRM850 supports all Private DataTAC system releases and topologies including Single, Multiple and General Frequency Reuse radio channel architectures.
The VRM 850 introduces Advanced Channel Loading (ACL) to allow improved single user inbound channel performance. Using the ACL feature, the VRM 850 detects channel loading and self-adjusts to maximize message throughput on a per device basis. Overall system performance will vary per system design on a per channel basis. Due to the utilization of new and faster digital signaling processing device, the VRM 850 may also show overall improvement in receiver Bit Error Rate (BER) performance by comparison.
Use of the Connection Management features of the Radio Data-Link Access Procedure (RD-LAP), makes inter-site roaming automatic and efficient. Channels are selected on a priority basis from a dynamically maintained or pre-programmed list, and the connection is continuously evaluated for quality, to maintain practically seamless communications across a wide area network.
Radio Optimized for Data
The two-way radio used in the VRM 850 has a fast-lock synthesizer and fast transmitter turn-on/de-key time to maximize over-the-air message throughput.
Mobile Workstation Interface
Existing Private DataTAC applications are plug-and-play compatible and new applications are easy and straightforward to implement. It’s become even easier with Motorola’s new second generation Wireless Communications Software (MWCSII) middleware product (not included). MWCSII provides an industry-standard IP connectivity, making the radio network virtually transparent to the application.
Mobile Workstation Support
The latest generation of Motorola’s MW 520 and other third-party notebook computers can benefit from the faster (up to 38.4 kbps) serial port. The VRM 850’s 64 KB message store-and-forward feature can be enabled to receive, acknowledge and hold messages that are sent to the unit even when the laptop is not connected. A similar buffer is available for inbound messages.
Power Control Choices
Power-up can be controlled by either the front panel On/Off button, the vehicle’s ignition switch, or the mobile workstation.
The VRM 850 exceeds EIA specifications and adheres to Motorola’s strict standards for reliability and quality.
The VRM 850 supports a Global Positioning System (GPS) receiver via the auxiliary port as part of an Automatic Vehicle Location (AVL) system. The GPS receiver may be programmed to report autonomously at regular time and/or distance traveled intervals, or polled on demand by the host.