Serial Server Prototype (Emery)


Emery Worldwide wanted to replace old handheld terminals with new Pen-Based computers (PBCs). The old terminals used a serial communications server that interfaced to a network and a legacy system. One replacement concept included a new serial server with simplified interface to the network and legacy system. This serial server would receive two-way serial data from up to 40 PBCs and use the IBM MQ-Series middleware to move the data to the network.


Telxon Corporation (Seattle, WA)Potential customers: Emery Worldwide, Kaiser Permanente


I wrote a prototype application for Windows-NT that used a multi-threaded serial protocol to interface with multiple PBCs. The system used a Digi Xem smart serial communications board with a number of Ports/8em modules. The application created a thread for each COM port and allowed the PBC to use a ZMODEM file transfer to move the data to the NT server. The system was tested with multiple devices communicating simultaneously and successfully transferred files to the NT server. The files were then reformatted and moved to an MQ output queue. The system used a Windows GUI interface with a live status display for each communication port.


The customer decided to use an Ethernet backbone for data communications due to hardware improvements and advances in the handheld client devices.


This system would have allowed new technology terminals to interface with the legacy system. The system would have maintained an interface similar to the existing one with minimal changes to the legacy software.

Product Details

The server used the following hardware:

  • Compaq Deskpro server
  • Windows-NT Server
  • Digi Xem ISA board with multiple Ports/8em modules
  • Application developed using Microsoft Visual C++, Greenleaf COMM++ serial communications libraries, and IBM’s MQ-Series software for NT
  • System designed to use Telxon’s 1124 PBCs