Windows Mobile 6.5 Serial Hardware Accessories

During the peak enterprise deployment of Windows Mobile 6.5, serial port (RS-232) communication was the primary standard for interfacing peripherals with mobile handheld computers. Enterprise personal digital assistants (PDAs) and rugged handhelds frequently utilized physical serial connections—via rugged multi-pin interfaces, direct DB9 cables, or snap-on sleds—to integrate specialized data collection tools. This article outlines the common serial hardware accessories used with Windows Mobile 6.5 devices, focusing on magnetic stripe card readers and related industrial peripherals.

Magnetic Stripe Readers (MSR)

Magnetic stripe readers (MSRs) attached to Windows Mobile 6.5 devices were primarily deployed in field service, line busting, public transit ticketing, and mobile point-of-sale (mPOS) environments.

  • Snap-On Sleds and Expansion Modules: Manufacturers like ID TECH, MagTek, and Infinite Peripherals developed modular MSR sleds tailored to popular rugged handhelds (such as the Motorola/Symbol MC70 and MC75 series, or the Intermec CN3 and CN4). While physically clipping directly onto the handheld, these units internally routed card track data over the device's hardware serial pins rather than standard USB.
  • Tethered Serial Swipe Readers: Standalone 3-track MSRs used RS-232 cables with DB9 or RJ-style connectors to interface with vehicle docks, mobile printers, or field terminals.
  • Data Transmission: These readers communicated directly through mapped COM ports (such as COM1 or COM4). Card swipe data was transmitted as standard ASCII string buffers containing Track 1, Track 2, and Track 3 data delimited by sentinel characters (%, ;, and ?), allowing applications to parse the data streams directly without complex driver stacks.

Barcode Scanners and Imagers

While many enterprise handhelds included integrated scan engines, external serial barcode scanners were common for heavy-duty scanning and warehouse use:

  • Tethered Rugged Scanners: High-performance, long-range industrial scanners (such as the Symbol LS3408 or Intermec SR61) plugged directly into the serial port of vehicle-mounted or body-worn Windows Mobile terminals.
  • Pass-Through Rings and Wands: Wearable ring scanners connected through coiled serial cables to forearm-mounted terminals, outputting raw serial scan data via configured baud rates (typically 9600 or 115200 bps).

Portable Receipt and Label Printers

Mobile workforces relied heavily on RS-232 serial communication to output data to belt-worn thermal printers:

  • Direct Serial Printing: Manufacturers like Zebra (RW and QL series), O'Neil/Datamax, and Bixolon provided rugged serial cables connecting the mobile device directly to the printer.
  • Cradle-Mounted Systems: Vehicle cradles routinely broke out the handheld’s proprietary connector into an RS-232 DB9 serial port, sending print jobs to in-vehicle ticket printers using printer control languages like CPCL, ZPL, or ESC/POS.

External GPS Receivers

Before integrated GPS chips became standard across all enterprise devices, external GPS units were heavily utilized:

  • Serial GPS Pucks: Devices mapped external NMEA 0183-compliant GPS receivers over serial ports. Windows Mobile 6.5 managed this via its built-in GPS Intermediate Driver (GPSID), which read raw NMEA coordinate sentences from a physical hardware COM port and multiplexed the data across multiple software COM ports for simultaneous use by different mapping applications.

Serial RFID Readers

Early mobile RFID workflows used serial communication to read high-frequency (HF) and ultra-high-frequency (UHF) tags:

  • Add-On RFID Gun Grips: Snap-on handles containing RFID antennas communicated with the core operating system using the physical serial bus, transmitting hexadecimal transponder IDs directly to line-of-business applications.

How Windows Mobile 6.5 Handled Serial Hardware

Windows Mobile 6.5 treated serial accessories through traditional Windows CE architecture:

  • Hardware Interfaces: Most rugged devices lacked full-sized DB9 ports, instead featuring heavy-duty, multi-pin bottom connectors (such as Motorola's universal 16-pin connector). Adapters or snap-ons exposed the transmit (TX), receive (RX), and ground (GND) lines required for standard RS-232 communication.
  • Driver Architecture: Serial hardware communicated through the platform's standard serial driver (serial.dll). Peripherals typically did not require proprietary kernel drivers; applications simply opened the assigned COM port handle using standard Win32 API calls (CreateFile, ReadFile, and WriteFile) to stream data.