Mobile data terminal

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A mobile data terminal (MDT) is a computerized device used in taxicabs, courier vehicles, service trucks, commercial trucking fleets, military logistics, fishing fleets, warehouse inventory control, and emergency vehicles to communicate with a central dispatch office.

Mobile data terminals feature a screen on which to view information and a keyboard or keypad for entering information, and may be connected to various peripheral devices. Standard peripherals include two-way radios and taximeters, both of which predate computer assisted dispatching. MDTs may be simple display and keypad units, intended to be connected to a separate black-box or AVL (see below) computer. On the other end of the spectrum, MDTs may contain full, PC-equivalent hardware. The function and programability of the devices is similarly broad.

Technology

In the earlier days of computer-aided dispatching (CAD), many MDT's were custom devices, used with specialized point to point radios, particularly in applications such as police dispatching. While applications like taxi and package delivery often still use custom designed terminals, many CAD systems are switching to common (or ruggedized) laptops and Wide-Area Wireless IP communications, utilizing the Internet or private IP networks connected to and over it.

For many industrial applications, such as commercial trucking, GIS, agriculture, mobile asset management, and other industries, custom electronic hardware is still preferred. Custom terminals use I/O interfaces that connect directly to industry-specific equipment. They are usually environmentally hardened packages with power supply protection and robust memory file systems that greatly improve reliability and task efficiency. MDT solutions that are based on ruggedized consumer products or consumer available software will typically not have the life cycle duration expected in industrial applications, over 5 years.

Typical MDT Features
* 9 VDC to 36 VDC input power.
* Electrical transient protection, such as described in ISO 7637, Electrical disturbance on road vehicles.
* Serial port to connect to a satellite or terrestrial radio transceiver.
* Digital I/O to monitor external events.
* Removable medial or I/O port of retrieving data or upgrading software.
* Wide operating temperature -10 C to 70 C or better.
* Drop tested to MIL-STD 810E, which specifies multiple drops from 48" to plywood over concrete.
* Sealed against dust and liquid.
* Connections to industry specific equipment, such as J1708 data bus for commercial truck applications.
* Display technology specific to viewing conditions for the intended industry (LCD, TFT LCD, Vacuum fluorescent display, CSTN).
* Robust flash memory file system that tolerates power interruptions, such as those offered by [Datalight] or [M-Systems]. (A consumer grade device and some MDTs will use an equivalent of Microsoft´s file allocation table (FAT) which may be corrupted when write operations are interrupted.)
* Integrated un-interruptable power supply, which will ride through electrical brown-outs typical in vehicle installations.
* Internal 802.11b transceiver (depending on target application), possibly with external antenna connection.

A related device classification, specific to the transportation industry, is called automatic vehicle location (AVL). Mobile data terminals are often used in conjunction with a ¨black box¨ that contains GPS receiver, cell phone transceiver, other radio devices, or interfaces to industry-specific equipment. AVL devices may be simple stand-alone modems or may include operating systems with application space for the system integrator.

External links

[Datalink] is an Austrailian manufacturer of MDTs and AVL devices.
[Datalux], a US manufacturer of MDTs.
[Digital Dispatch Systems] is a Canadian manufacturer of mobile data terminals (MDT) and computer assisted dispatch systems.
[Dilupe] is a Belgium manufacturer and integrator of MDTs with satellite and cellular services.
[DriverTech] is an integrator and service provider of MDTs and fleet vehicle management products. The primary product is the Truck-PC. Features include interfaces to the J1708 and J1939 vehicle diagnostic data buses.
[Intellidesign] is an Australian contract designer of MDTs, single board computers, and industrial computers.
[Intermec] is one of the largest international, publicly traded, manufacturers of mobile computers and other high-tech products.
[JLT], a manufacturer of MDTs, is based in the US with a sales office in Sweden.
[JuniperSystems] is a small focused US manufacturer of high quality, rugged, portable data terminals used in GIS, agriculture, and other field environments.
[Kenwood]´s KDS-100 is a simple MDT that can be used with Kenwood or other radio or AVL products for feet management tasks.
[LIVODA] is the mobile courier and logistics device with signature capture, bar code scanning, GPS as well as additional features and products.
[LXE] manufacturer of a full line of MDTs and portable terminals for asset management, inventory control, logistics, and fleet management. Features include bar code scanners, wireless interfaces, voice, and heaters for cold environments. Sales offices in many countries.
[MaxTrack] is a Brazilian manufacturer of MTDs and AVL devices, as well as a network service provider. Their MTC-600 has been featured in an ad campaign by Analog Devices for their Blackfin processor. Fala português?
[Mentor Engineering] is a Canadian contract engineering service with expertise in MDT design.
[Microbus mobile data] is a UK manufacturer of mobile data terminals.
[Micronet] is another contract engineering service for MTDs. They are based in Israel.
[Punch], based in Belgium, Punch has offices in France and the Netherlands.
[QSI] is a US engineering and manufacturing organization focued on MDTs and panel-mount industrial terminals.
[Symbol] may be the largest MDT manufacturer.
[TDS], US, is a manufacturer of portable data terminals. Primarily focus is serving GIS applications.
[Two Technologies] manufacturer with full range of hand-held computers based in the US.
[Wescor] is a small, diversified organization with a division that has focused on OEM mobile data terminal and AVL computers for over 12 years. Their low-cost, rugged, open platforms are targeted to value-added resellers and system integrators with features tailored to the commercial trucking industry.

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