DATA-LINC GROUP
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LCM100 User’s Guide
Note:
If a three-to-two-wire adapter is used to connect to a two-wire AC outlet, the ground lead
of the adapter must be connected to earth ground to complete the ground system. An open
ground connection may cause a communications defect and/or shock hazard.
Line conditioners in the form of isolators, regulators and surge protectors may be present in the
computer system in order to provide clean power, especially on non-dedicated lines. The
LCM100 has integral surge protection.
Note:
The LCM100 should not be plugged into isolator or surge protector devices as this may
cause signal degradation. If Detect indicators do not illuminate with both units connected to line
power, a coupling capacitor may be required for cross-phase communication (see appendix B).
Initial Operation
The LCM100 is completely transparent. This means that once the system is correctly installed, it
will not be apparent to the system. Like a cable, it requires no attention other than a reliable
connection.
With the modules connected to their respective equipment as previously described, ensure that
both module’s, Detect and Power indicators are illuminated. Data transfer will occur in both
directions as commanded by the interconnected equipment.
Sometimes a random glitch on power lines will cause erroneous data characters to appear at
either end of the communications line. This is to be expected, especially during periods when the
equipment is idle. Error correction procedures appropriate to your computer operating system
can be taken to remove the spuratic characters.
Troubleshooting
The following are methods of eliminating the cause of communication difficulties, which may
occur with the LCM100.
Fuses
Each module has a fuse located internally. Replace only with a fuse of similar rating of ½ amp 3
AG.
Troubleshooting Technique
If communication difficulties are encountered, first check for proper cable connections at the
power receptacles, and at both RS-232C interface cables. An indication of faulty FSK
communication between modules is a missing Detect indicator at either module. An indication of
faulty power line connection is the missing power indicator at either module.
To isolate a communications problem from the RS-232C interface, simply connect the equipment
directly, without going through the LCM100 modules. If the problem persists, then the defect
probably lies within the equipment and not the LCM100.
To isolate line carrier problems from the power distribution circuits, connect each module’s
power receptacle into a common power distribution circuit—for example, at the same outlet or
through an extension cord. If communications occur at one outlet, but not at another, then the
problem is probably due to lack of coupling between phases.
Note:
The LCM100 does not use the handshake lines; therefore, communication protocol codes
will possibly need to be implemented in order for the LCM100 to operate effectively.
PN 161-09998-001A
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