Auto-Zone Control Systems Auto-Zone Basic Systems Installation & Operation (Version 02C) - Manual (Page 139)

Auto-Zone Basic Section 4
Start-Up & Troubleshooting 4-37
CommLink IV (Optional)
CommLink IV must be powered for testing.
If the voltages are too high or too low on either side, the CommLink IV has a damaged
comm driver chip. Replace the CommLink IV. The driver chip is not field replaceable.
Basic System with CommLink Installed
Measure Voltage
T to G + 2.5 to 2.4 VDC
R to G + 2.7 to 2.5 VDC
If the voltages are within the specified voltage ranges, the Zone Manager and communi-
cation loop are operating within specifications. If the measured voltages are not within
the specified voltage ranges, proceed to Step 2.