Coyote modem and communication port signal testing – Gasboy Enhanced Communications User Manual
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MDE-4520C Enhanced Communications Installation Manual · February 2008
Page 27
HyperTerminal Test
Coyote Modem and Communication Port Signal Testing
Note: The CDR 915 is compatible with the CDR 9150 modem. With the differences noted
below.
• When the modem is plugged into power, it should show a YELLOW light on the front
near the connector. It should also flash the GREEN light approximately once per second
even if no second modem is in the area.
• If the green transmit light is not flashing, plug and unplug the power connector to the
modem. This can happen if the communication cable is inadvertently disconnected and
reconnected. If this continually happens, use an ohm meter to verify point-to-point
connection, if necessary.
• The pin outs are referenced to a 9 pin connector for voltage measurements. Refer to the
if conversion to 25 pin outs need to be made.
• The CDR 9150 does not provide Pin 1 DCD. It provides the Pin 6 (DSR) and Pin 8 (CTS)
signals. Sites that are replacing a CDR 915 with a CDR 9150 must ensure they order the
new cable listed in Appendix A,
PC to Wireless Modem (Cable made up of Q13850-15,
on
or modify the existing cable to provide the Pin 1
to Pin 6 jumper as shown in the table
.
• The signals between Gasboy system and modem or between PC and modem may be
verified by the use of an RS-232 Breakout box. An LED will verify the presence of the
individual signals. They may also be measured using a Digital Volt/Ohm Meter. Ensure
that you do not short the pins. Those voltages are provided below. The wireless modem
need not be connected to a PC or Fleet system for the tests below. If the wireless modem
does not provide the proper communications signals, it indicates a bad modem and a new
one should be ordered.
• Use Pin 5 for signal ground.
• If measured at the modem (no cable attached):
- Pin 1 (DCD) is measured to be 6.8 VDC nominal (CDR 915 ONLY).
- Pin 6 (DSR) is measured to be 6.8 VDC nominal.
- Pin 8 (CTS) is measured to be 6.35 VDC nominal dropping to below 6 VDC when the
GREEN transmit light flashes on the CDR 915.
• When you are using the cable mentioned in
with
Pins 1 and 6 jumpered internally, the voltage will be 6.35 VDC nominal if measured at the
9 pin connector that will plug into the PC.
• These voltages may vary slightly due to the meter used.
• The PC needs to provide two communication signals. To test these signals a
communications program such as Hyper Terminal must access the communication port to
be tested.
Note: The Coyote Radio Programmer software only provides the DTR signal.
• Pin 4 (DTR) Hyper Terminal and Coyote Radio Programmer software.
• Pin 7 (RTS) Hyper Terminal software only.
• Both of these signal should measure 5.5 VDC nominal.
• If these two signals are not properly provided by the PC's communication port, a problem
with the PC communications port is indicated. Use a second port on the PC if available.
Have the PC repaired as necessary.
• With the Wireless modem connected to the PC, all five signals (DCD, DSR, CTS, DTR
and RTS) must be present for the Gasboy software to properly work with the wireless
modem. All five signals are not easily verified with the cables connected without the use
of a RS-232 breakout box.