Serial Port to Serial Port Switch

1
Serial Port to Serial Port Switch
Design team May03-11
Faculty Advisor CPR E CPR E CPR E CPR E
Dr. Doug Jacobson Michael Clement Jason
Gordon Brian Hof Connor Reynolds
0101100101101111011101010010000001100001
011100100110010100100000
01100001001000000110111001100101011100100110010000
101110
Abstract
Design constraints
This project requires the design of a new serial
port switching matrix to replace a current
installment specifically to design, build and
test a switching solution that will be used as a
backup to Union Pacific's main system. The
system is used to control connections to remote
sites that monitor train movement, control and
verify settings of track switches and indicators.
The main goal is to find or design the hardware
to physically connect the serial modems to the
centralized track controller (CTC) and design
software to control the data switch matrix. The
system ensures connections to the CTC without
user intervention. It is crucial that
communications with remote sites are maintainable
and by routing data through this control matrix,
information will get to its destination with
little or no human intervention.
The system must interface with existing modems
and CTC processor. Union Pacific has already
established a way to communicate between the
remote sites and a central location. The switch
must take the existing modems and connect them to
the CTC.
Measurable milestones

• Finalize product description with Union Pacific
• Develop a design architecture
• Acquire hardware and assemble system
• Develop software system
• Test software with hardware
• Integrate with Union Pacifics system

Acknowledgement
Thanks to Gerry Mann and Rick McCormick for their
guidance and Union Pacific for financial support.
End-Product description
The scalable RS-232 serial data matrix switch
shall be capable of connecting at least 256
serial connections to a centralized controller,
with individually configured ports. The matrix
switch shall connect any number of serial
connections, but in this case has been tailored
to meet the needs of Union Pacific. The
controller will be used as a backup system to
send data between a CTC and remote systems via
modem.
General background
Union Pacific is in need of an automated system
that connects and routes information traffic with
little user input as a backup to their primary
system.
Technical problem
Technical Approach
The problem we are solving is to replace a set of
switch matrixes with a new design that
incorporates new functionality and easier
expandability. The current system that Union
Pacific is using is based on hardware switching
matrixes that are limited in their functionality.
The problem is reduced mainly to a software
problem by using off the shelf USB to 16 port
RS-232 serial devices and writing custom software
to handle all switching, routing and user
interface requirements that Union Pacific
desires.
The selected approach is to use USB-to-RS-232
hardware in conjunction with a single laptop
computer running custom switching software to
control all of the routing and configurations of
the serial ports. This approach offers more
advantages than disadvantages. The system itself
would be easy to set up, requiring only enough
USB devices to support the total number of serial
ports required. This has implications for
expandability, as well with properly developed
control software, adding serial ports would be as
simple as purchasing more USB devices. These
devices are relatively inexpensive, offering yet
another advantage. A disadvantage associated
with this design is the complexity of the control
software that will be required to maintain the
matrix of ports/devices.
Operating environment
The system runs indoors in a climate-controlled
room near the CTC. This is an ideal environment
for the system. There is little or no risk of
problems related to temperature, moisture, or any
other elements that may disrupt the system.
Intended users and uses
Users The users shall be educated Union Pacific
employees with moderate computer skills. There
shall be 3 levels of security allowing
administrators to perform operations that the
general users are not allowed to perform. The
administrators have more knowledge of the
system. Uses The system shall be used as a
backup system it is not intended to handle the
entire load of the system for long durations of
time, but will be capable if unforeseen problems
occur.
Testing Approach

• Test USB-Serial Devices and determine scope of
  interface software to be written
• Write interface software and test against CTC to
  confirm that communications can take place
• Testing each generation of software with one,
  then expanding to many port connections
• Build support for required number of ports as
  well as specific requirements provided by Union
  Pacific
• Completed system will be field tested against
  normal use cases and scenarios

Assumptions and limitations

• Assumptions
• The system shall replace the current system
• Union Pacific will be requiring 30 modem
  connections at the present time
• System needs to be expandable in the future with
  minimal system change
• Limitations
• The system will be using RS-232 serial port
  connections and settings
• The system must connect to existing modems
• The system must connect with the CTC as their
  current system does

Personnel Effort
Design objectives

• One computer to connect COM ports via USB
• As many external RS-232 connections as required
  by Union Pacific
• Software to route information from modems to CTC

Budget
Functional requirements
Item Cost
Poster 60
Control PC 1200
USB Serial Cards 1200
Total 2460

• Pass information from remote sites to the CTC for
  data collection and control
• One to many connections- scalable to 256
  connections
• Software must auto-redial connections without
  user input in case of disconnection
• RS-232 interface, must be compatible with
  currently installed modems
• Configurable RS-232 settings and asynchronous
  speeds

Omaha, NE