| Technical Tip
# 3
How to best make use of a
WAN Breakout Box.
WAN BOBs or RS232 BOBs with
12-24 LEDs have dedicated DCE and DTE sides, making the interpretation
more difficult if interfaces are not matching. Starting with open switches
is the best right method.
Step
1: Open ALL in-line Switches and insert the
BOB in the to be tested circuit.
All circuits lighting
means you are dealing with matching interfaces (DTE-DCE), no circuits lighting
mean matching interfaces but on the wrong side of the BOB. If the LED light
only on one side the interfaces are of the same type. Check for strange
or missing signals.
Step
2: Test GPD if both units are using
different wall outlet.
This test is seldom
made, GPD changes. It can be present in a small extent today, tomorrow
(or in several months) your system can stop to later just function again.
All switches open allow for
a GPD test between the right and left Signal Ground sockets of the
breakout panel. You can do this with a DVM, our BOBs have build-in circuitry
to test GPD. GPD comes from the electric distribution system. Tech.Tip
# 4 explains GPD in detail.
Step
3: Close the Signal Ground Switch.
Knowing with which
kind of interfaces you are dealing interfaces with you know if you have
to cross patch our can "just close switches". Work line by line, connecting
control line often brings a change in response from the other side
(RTS is answered by CTS).
RS232 control lines often
require strapping, done in the connector on the terminal.
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