Telxon PTC-710 Information

This page details the Telxon PTC-710 handheld barcode scanner from the perspective of a hobbiest interested in hacking around on it, and running/writing custom programs for it. The bulk of the work here was done by ChartreuseK and TangentDelta. Information was gathered through reverse engineering the BIOS as well as probing the hardware and software.


Hardware Overview

The Telxon PTC-710 is a x86 based handheld computer/barcode scanner designed for commercial data collection, organization, and logging.

System Specifications:

Software Overview

The Telxon PTC-710 is designed to run two different operating systems, either Telxon's TCOS (TCAL Operating System) or Microsoft MS-DOS. This was a purchase option and each comes with a different internal program ROM (removable). The choice would be down to which platform your business application was designed for, and which you wanted to write it for

TCOS -- TCAL Operating System

Due to it's propritary nature we know less about TCOS and development for it. TCAL is the Telxon Common Application Language, and was a proprietary language and is believed to be Cobol based.

ROM Dumps containing TCOS:

Microsoft MS-DOS 3.2

The PTC-710 also can run a version of Microsoft MS-DOS 3.2. The version appears to be largely unmodified, instead relying on a custom BIOS implementation for compatibility. This makes the PTC-710 more of a MS-DOS compatible machine rather than a PC compatible machine, though it does have some concessions to PC Compatibility in the mapping of some hardware.

The filesystem used for both the boot partition (C:) and the option rom (B:) is standard FAT12 though with a limited number of root directory entries, and is quite picky about the format. I was able to create the Blank FAT12 ROM image by first formatting it with:

mkfs.fat -F 12 -M 0xf9 -s 1 -S 512 -f 1 -h 0 -r 16 -R 1 -n "MSDOS3.2" blankdisk.rom 

Then copying over the boot sector from a known working ROM and adjusting the sector count. Not ideal but it wasn't happy with my image. The issue may have just been the head and sector/track count as it's basically treating these ROMS as a floppy so the following command may work instead:

mkfs.fat -F 12 -M 0xf9 -s 1 -S 512 -f 1 -h 0 -r 16 -R 1 -n -g 2/9 "MSDOS3.2" blankdisk.rom 

For these blankdisk.rom was just a 128kB zeroed file, you can create this with dd.

dd if=/dev/zero of=blankrom bs=1024 count=1024

I've since learned of someone who has 256kB ROM chips in their PTC-710, so you can likely put a 256kB ROM in and make a corresponding FAT image for that.

With this blank image created you can simply mount the image with a loopback or use a tool like WinImage on Windows, and copy files onto it. Note that the image only has 16 root directory entries so you may run into that limitation if you copy more than a couple programs onto it. I have not tested if the BIOS is fine with images with a longer root filesystem, or if you'd just need to store additional files in directories.

ROM Dumps:

Under Construction