38 Troubleshooting 6 QUCM Modbus ASCII Modem Application ManualTable 6-2 QUCM User Light DefinitionsTable 6-3 MUCM User Light DefinitionsTesting the RS-485 network on the MUCMZapreg32 may be used to quickly test the RS-485 network at the QUCM.1 Verify that the switches 1 and 2 are in RUN and that the RN1 light is on.2 Connect the meters to the MUCM’s RS-485 port.3 Verify that the meters have the correct slave address, baud rate, and parity.4 Connect the PC to the MUCM RS232 port with an MU1 cable.5 Verify that the MUCM has the same baud rate and parity by using zapreg32.>zapreg32 com1:9600,E,8,1 255 -ato start zapreg32 in Modbus ASCII mode.Move the cursor to the Register column and enter the number 300. and press en-ter. The meaning of each register is shown in Table 6-4. Press ESC when fin-ished.6 Communicate with each of the slaves using zapreg32 in Modbus ASCII mode.>zapreg32 com1:9600,e,8,1 1 -awill try to communicate with slave 1 in Modbus RTU.>zapreg32 com1:9600,e,8,1 105 -awill try to hit PNIM slave 5.Light Meaning1 Flashes quickly when no devices are configured.2 Toggles as the QUCM steps through the devices for port 1.3 Toggles as the QUCM steps through the devices for port 2.4 Comes on when the Modem on port 1 has DCD.5 Comes on when the Modem on port 2 has DCD.6 Not used.7 Not used.8 Not used.9 Not used.10 Comes on while the debugging telnet server is connected.Light Meaning12 Comes on when the Modem on RS232 port has carrier (DCD).35