Mobile Data Terminal (MDT)

REVISION 07/31/07


The Motorola MDT products were all uniquely configured to meet the needs of each client. The following is based on individual units from first-hand experience, your mileage will vary. Please direct comments to Eric Willman at mdtdata (at) willmantech add a dot com.


Test and service mode:

After unit boots up, push the "FORMS" key, then the "T" key then "E" key.

This brings up the service menu:

A      P. O. S. T.   test 
1       EEPROM test 
2       Radio test menu   (password 1-2-3-4-5) 
3       Configure EEPROM  (password 1-2-3-4-5) 

        1. terminal parameters 
        2. radio 1 setup 
        3. radio 2 setup 
        4. ACT parameters 

4        software ID / version 
5        keyboard test 

You may need this programming dongle to access the test mode above.


The 9100-11 is an EPROM based Mobile Data Terminal. The unit tested is a model D3003A (9100-11.) There is a wide access door on the bottom front that contains the EPROMs for the unit.

The unit contains a basic operating system on U5 that appears to be a proprietary system. U7 on this unit is populated, but doesn't have a label on it. U6 is labeled as the TX (transmit) EPROM. U22 is also populated but is labeled as "blank."

There appears to be a custom "personality" PROM in U206 that contains the programming for the specific functions of the unit. If you remove this personality PROM, the unit will function as a basic terminal.

A quick glance will look as though the EPROMs are soldered in but are really pluggable onto the circuit board. Careful removal is required to not bend the pins on the bottom of the chip. There is a soldered in button type battery to the left of the EPROMs.

There is a flying pigtail power connector coming out of the radio PA deck. This powers the entire unit. If you remove the radio unit, the same connector type is used as the power feed to the terminal. That connector is plugged into the radio. The radio can be removed and the same power connector plugged directly into the terminal to use it without the radio.

The unit responds to simple 2 letter commands. Not all of them have been figured out, but the following is a list of ones that have been found so far:

The unit appears to have standard serial com ports on the bottom. These ports are viewable using the MOde command referenced above. There would also be a printer port.

Not much time was spent on this unit so the info discovered is limited to the above.


This unit is a PC wrapped up in a special package. It actually contains AMIbios (American Megatrends Inc) that can be accessed during boot-up.

The units tested contain 4MB of RAM which operates as standard PC memory and 4MB of NVRAM which operates as a flash type disk drive. This disk drive does not allow random access as a typical drive. There is a utility that allows for updates to the system (explained below). This makes the MDT exist with no moving parts. There aren't any shock issues to be concerned about with a hard drive.

There is a rechargeable NiCad battery pack on the bottom below a metal cover that maintains time/date and BIOS settings. The battery pack contains 6 cells and you can use 2x3 cell cordless phone battery packs in series to replace this unit.

The keyboard contains all the same keys as a standard AT computer keyboard. Only the locations may be slightly different than you are accustomed to. The F-keys are located next to the display. The large red button can be used as an emergency or Xmit key (depending on software) and has a DOS scan code that can be monitored. These keys have custom backlighted legends depending on the software in use.

The display is an amber monochrome 80x25 screen that can be changed using DOS MODE commands. Get your old DOS book out to change this to a 40X25 screen for much larger letters.

There are 2 PCMCIA slots on the right side of the unit. These are old PCMCIA slots that support 16 bit "PC-cards" (NOT 32 bit "card-bus" type cards. If your card has a brass grounding strip on the top then it will NOT work in this slot.)

There are several different configurations of connectors on the bottom of the unit. These units have 2 DB-9 connectors for COM1 and COM2. These appear in the BIOS and appear to be standard PC com ports. A male DB-25 connector should be for the printer, but it is the opposite gender of typical printer ports. Perhaps that is due to the lack of standards back when this was manufactured.

A hard reset switch is also included. AND, surprise, there is also a SCSI port! Toward the front is a proprietary docking port connector with a plastic cover on it. A 15 pin female connector is used for a radio interface. There is currently no more info on this port.

These units have a small 800Mhz exciter coupled to a Maxtrac style PA deck. The PA deck requires a separate source of 12VDC to operate. The exciter is plugged into a multi-pin connector under the unit to interface to the radio. The radio has markings on it for deviation adjustments, output, etc.

You can add more RAM using 2 internal 30 pin RAM slots. Two 1MB sticks were added to the test unit and the system reported 6MB of RAM during BIOS memory checks.


The system BIOS will prompt with the key (HOME) to enter the BIOS settings. Once inside, the system looks like any other computer BIOS setting. The default seems to work fine.

During a normal system boot, the computer will set-up an MS-DOS RAMdisk and copy several Windows files here for random access. There is what appears to be a rather convoluted system of boot-up procedures with the autoexec.bat and WINCPY.bat files. The files have lots of references to each other and if you print out the files that are referenced, you can see how the system booted properly and what was intended.

It is much easier to simplify this whole back and forth thing and replace it with a simple command structure in the autoexec.bat file during boot-up. It should be noted that some care is required, particularly in the config.sys file, because you will most likely need and/or want the drivers and utilities that are loaded, so don't go too crazy.

Note that one would also expect that you could easily brick the box by deleting too many things at once and not having the resources to fix your goofs!


During boot-up, there are a ton of options and drivers that load and flash by on the screen. One of the options that is significant is the ability to press CTRL-SHIFT at the right point to enter a special system mode. The screen will prompt you to confirm that you want to continue. You need to answer Yes.

This will run x:\dos\MIRROR_C.sys and loads the entire "c:" drive NVRAM into the RAM as a form of a RAMdrive. The NVRAM is always c: and the RAMdrive is d:. The NVRAM can never be edited directly.

Once here, you will be able to make any changes that you wish in the RAMdrive that will ultimately be written to the NVRAM image. After you are complete editing, you type SYNC and the system will write the entire new file structure from the revised RAMdrive to the NVRAM and reboot. This will make the files permanent.

You must do this before you reboot the machine or all your changes will be lost, just like a regular RAMdrive. This also means that applications and start-up issues need to be tested and taken into account what is accessed from the "c:" drive during boot and what needs random access from the DOS RAMdrive on the "d:" drive and needs to be copied there.

Getting files onto the system is a bit trickier. Since there is no floppy drive, you need to find an alternate method of moving files. Note that there are several programs on the system to facilitate file transfer. In the old days of DOS, they used x:\dos\INTERLNK.exe and x:\dos\INTERSVR.exe as a DOS version of LapLinkŪ.

You can use a standard LapLink serial cable and run intersvr on one machine and interlnk on the other. This basically maps all the drives between both machines. The system will tell you what drives are mapped to which drive letters. This is fairly straight forward, and you can copy files from machine to machine using DOS copy commands and the correct drive letters.

It actually works like mapped drives in today's Windows environment. The floppy, HD(s) and even the CD-ROM drives all get mapped to letters for transferring files.

One of the first files that need to be put on the system is or some other editor for text files. You will need this to edit autoexec.bat and config.sys to get the system customized. You can inhibit the starting of Windows by removing (or placing a rem in front of) WIN from the autoexec.bat file on the D: drive. If you want to run Windows, you will need to edit that startup.grp file to stop the auto execution of the MDT/radio programs. If you miss this step, the system will enter "TX for Windows" and the system was originally set-up in a deliberate loop to inhibit the operator from ever "breaking" the system by allowing it to drop to a Windows screen.

You may find it necessary to delete the SYSSW and/or the TXWIN directories in order to free up some space on the drive. If you don't plan to use any of the system MDT or radio software, these are just in the way. Remember, you will need to SYNC after all your changes are made.


The computer boots up with the DOS operating system and actually runs a stripped version of Windows 3.0. You need to be able to run the system without a mouse. You may need to grab the old Win3 manual to remember everything.

Once booted to a Windows screen, it will look just like the old days and allow you to run File Manager or any of the other Windows functions. Remember, this is a very stripped down version but ALT-F-X still exits the system (if you fixed the loop in the autoexec.bat file).

The only files that are on the system are those required to run Windows in this mode. There are no frills on this system because of the 4MB NVRAM capacity. The main operating application is "TX for Windows". This is Motorola's program for interface to the radio and data network. It provides all the operator interface for reports, status, and dispositions. This is customizable using "forms" and other scripts. There exists a document on the web that covers this application. If you're interested, hunt it down.


There are several directories that contain drivers (as they were for DOS) and utilities. You will want to take great care in changing these files as they are specific for the computer hardware in front of you. The x:\cardsoft directory contains several software items for operation of the PCMCIA slots. Several of these programs have not been fully explored as of yet, but here is a partial list of the ones that have.

MEMCARD.exe is a program to set up and configure PCMCIA memory cards. These are believed to be memory cards that could work like RAMdrive. A memory card that WinXP won't even see has been tested, yet it works like a drive in the MDT.

One (or several) of these files are used to read and write compact flash cards that can be used with a PCMCIA adapter in the slot. A standard PCMCIA to CF adapter card can be purchased and plugged it right in. Up to 16MB CF cards have been tried so far. 32MB and larger don't seem to address properly. Several 10MB flash disks off Ebay have been tried and have been trouble getting them to work on the MDT.

You neede to use the FLASHFMT.exe program in the directory in order to write the required signature on the card. These units now function just like a standard disk drive using the correct letter. The default drive letters are G: and H:, depending on the slot the card is plugged into. The same cards can now also be plugged into WinXP.

The S_IDE.exe driver program is started at boot to access those disk cards.

CS.exe is SystemSoft Card Services driver started at boot. CIC.exe is SystemSoft Card Installation Client started during boot. Both of these must be loaded at boot for anything in the PCMCIA slots to work.

You could probably put a 3com network card in there with the appropriate DOS drivers and it would take off and run. The card will beep when it is put it in, but one would need to take the time to get all the driver files in the right place for DOS.

The x:\dos directory also contains some DOS drivers such as HIMEM.sys and a small program called Typing OFF at a command prompt will turn off power of the system. This is where you would want to put the text editor program since it is in the DOS path command.

In the config.sys file are a number of utilities that are started to allow for many operations. Caution in editing as advised above applies here. A partial list is below.

x:\dos\ starts a driver for scsi hard drives via the local connector.

x:\dos\interlnk.exe starts an interlink driver. We have REM'd this one out.

All of the drivers for the card slots are loaded in config.sys. The BUFFERS, FILES, and STACKS statements are included in config.sys.

Since this is a standard computer, you could load extended memory managers and any other TSR programs that you may desire to complete your system. You are of course limited to the capacity issues of the 4MB NVRAM. However, with the addition of PCMCIA drives and memory cards, the NVRAM is only truly needed for the start-up environment. This makes this system a very powerful little computer for a heavy duty mobile environment. This little unit can take a lot of extremes and rough use.

From what's been seen, the 9100-T is basically the same looking unit, but it lacks the SCSI port on the bottom of the unit.

We have no experience directly with a 9100-T, but it also runs windows 3.0, and is probably very similar to the info above. It may have a different processor and/or RAM configurations.