Typical RS232 Wiring

The following diagrams depict the cable wiring between a DNC workstation's communications ports (either the standard built in COM1 and COM 2 or Rocketport expansion ports) and most CNC's. The numbers given are for standard 25 pin D-subminiature RS-232 connectors. On the PC side the connector must be a socket. On the CNC side it varies. FANUC and Yasnac's, for example require plugs. Okuma's and Cincinnati's generally require sockets.

If you are going to use the standard COM 1 and/or COM 2 ports that happen to be 9 pin plugs, we recommend using a 9 to 25 pin adapter so that all of your cabling can be alike and that they can be more easily serviced when a data tester (break out box ) is required for debugging. We have, however, included wiring instructions for both 25 and 9 pin styles.

For serial hubs which use RJ45 (telephone style connectors), we supply adapter cables to convert from RJ-45 to 25 Dsub plug connectors whose pin outs are the same as standard P.C. COM ports.

What kind of cable to use

In any factory environment shielded cables are essential.  We recommend shielded cables designed for RS-232 communications.  It is 24 AWG (American Wire Gauge) and designated as "Low capacitance computer cable."   Sometimes you need only three conductors but other times you might need 5.  If there is ever a need to use RS-422 communications, such as, cable runs greater that 300' or very electrically noisy environment each signal requires a pair of wires.   Therefore, we recommend using the following:

Overall foil shielded, 3 twisted pair, 24 AWG, stranded, low capacitance computer cable. We use Carol CO901 or Belden 1420A.