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10.4 Problems Interfacing Serial Devices
Most problems experienced with connecting serial devices are caused by
incorrect cabling or incorrect handshake/protocol settings. Do not assume
that, because a cable has the correct connectors and works between two other
devices, it will work when connected to the Modular Smart Switch. Always use
the cabling specified in this manual (see
Appendixes A
and
B
). Incorrect
cabling may cause many different problems, such as:
• No data transmission
• Loss of data, corrupted prints and plots
• Unreliable file transfer
10.5 Serial Interfaces—No Data Transmitted through the Switch
Check that you can send data between your devices using a direct connection.
If you can’t, check your devices. If you can, connect the Modular Smart
Switch and try sending a small amount of test data.
If the input channel indicator comes on, then no data is being sent into the
switch—check the cable between your PC and the Modular Smart Switch, and
check that you are sending the data from the correct port on your computer.
If the channel indicator flickers or comes on, then data is being transferred
into the Modular Smart Switch.
If no data appears to be transmitted out from the Modular Smart Switch,
then check the cable between the switch and your output device.
If the channel indicators go out after the timeout period (usually 16
seconds), then all the data has been sent out of the switch. If nothing appears
to have been received on your output device, then check the protocol (a
protocol problem often causes the data to be changed into a stream of null
characters).
10.6 Serial Interfaces—Corrupted Data
The most common cause of corrupted data when using serial interfaces is a
handshake problem. If you experience corrupted data when using serial
ports, check that the protocols set on your equipment are the same as those
set on the Modular Smart Switch. If you are using hardware handshake,
check that the hardware flow-control lines are connected on your cable.
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10. Troubleshooting
The Modular Smart Switch is designed to a high standard and all units are
fully tested before leaving the factory. There are no user-serviceable parts.
If a fault persists, please contact technical support.
10.1 Self-Test at Power-On
The Modular Smart Switch automatically tests its basic operation when it
powers on. The buffer indicators flash for a few seconds while the test is
being conducted and go out when the test has passed. If the buffer indicators
do not flash or do not go out, then there may be a problem—consult
technical support.
10.2 Parallel Interfaces—No Data Transmitted through the Switch
If you have problems transmitting data through the switch using parallel
interfaces, make sure that the direction (input or output) has been set
correctly—see
Section 4.2
. If you have any problems in transmitting to
parallel ports, do not use the automatic in/out detection setting, because
this is not guaranteed to work with all printers.
The channel indicators show whether data is being routed correctly from
one port to another.
10.3 Parallel Interfaces—Corrupted, Extra, or Lost Data
Problems with corrupted data when using parallel communication are rare.
When problems do arise, they are mostly cabling problems. Avoid using
ribbon cables. Use shielded cables and keep the length to 22.9 ft. (7 m)
or less where possible. Problem cables can cause occasional data corruption
and spurious page feeds on laser printers.