8 - PC400 Terminal Installation & User’s Guide
RS-485 Connections
An RS-485 connection can attach up to 31 clocks to the computer, using a SWIFT-485+ converter that you can purchase from Lathem. You can wire the clocks directly to the converter (star configuration) or wire them to RS485 Terminal Screws; this allows you to run in a single line starting from the converter (multi-drop configuration).
With an RS-485 connection, you can use up to 4000 feet of cable to connect your clocks to the computer. Lathem recommends using CAT 5-UTP (unshielded twisted pair) data transmission cable.
To make an RS485 connection
♦Connect a SWIFT-485+ converter to an open COM port on your computer. If your COM port has 25 pins, you will need a 9-to-25 pin adapter that you can buy from a computer store.
♦Run the CAT 5 cable from the Swift-485+ to the first clock in the series . See Appendix A for the RS485 Network diagram
♦Unplug the RS485 screw terminal connector and attach a matched pair from your cable as shown in the diagram, plug in the connector. Make sure that the polarity is maintained. If your cable is terminated with a RJ-45 plug connect to the Terminal’s RS232 / RS485 communications port as shown in the diagram below, Figure 4.
(-)(+)
| RS485 Screw | RS232/RS485 |
| Terminal Connector |
| Port |
| |
