APPENDIX B
TROUBLESHOOTING
SYMPTOM
PROBLEM
SOLUTION
LEDs do not light
when AC power
transformer is
plugged into wall
No data transfer in
either or both
directions
1. Loose power
connection
2. Outlet is defective
3. AC power cord is
defective
4. The AC transformer
is not plugged into the
Model 1070
1. Improper twisted
pair wiring
2. Improper bit rate
setting
3. Distance
specifications
exceeded
1. Make sure the AC
connection is flush
2. Try a different outlet
3. Remove the cord
from the outlet and
check for continuity
4. Have another cup of
coffee!
1. Compare your
twisted pair wiring with
the diagram in Section
4.1
2. Ensure all bit rate
settings on all
connected serial ports
are the same
3. Check specifications
in Appendix A
17
APPENDIX B
TROUBLESHOOTING
SYMPTOM
PROBLEM
SOLUTION
"TD" and "RD" LEDs
indicate activity, but
units will not
communicate or
data is garbled
"TD" and "RD" LEDs
indicate activity, but
"CD" LED is unlit or
red (should be
green)
Occasional data
errors
1. Improper RS-232
wiring
2. Improper twisted
pair wiring
3. Improper bit rate
setting
1. Defective twisted
pair line
2. Poor twisted pair
connection to Model
1070s
1. Distance/bit rate
capacity exceeded
2. Poor quality twisted
pair circuit
3. Poor twisted pair
connections to Model
1070s
1. Check wiring
between Model 1070
and connected DTE
device—it should be
straight through
2. Compare your
twisted pair wiring with
the diagram in Section
4.1
3. Make sure the bit
rates on all connected
serial devices are the
same
1. Test continuity of
twisted pair line
2. Check screw
terminal/RJ-11
connections to Model
1070s; check integrity
of plug RJ-11
terminations
1. Check specifications
in Appendix A
2. Use a different
twisted pair circuit
3. Check screw
terminal/RJ-11
connections to Model
1070s; check integrity
of plug RJ-11
terminations
18
