Envision Peripherals NV3128 - Manual (Page 40)

NV3128 RS-422A Machine-Control Routing Switch 2-16
RS232 (OBSOLETE):
The NV3128 Control/Command Interpreter interface is always a DCE
device when operating in RS-422A mode. As shown above, the system
can be configured as either DTE or DCE equipment in RS-232 mode.
It should be noted, however, that the selection of DTE or DCE involves
only the exchange of pins 2 and 3 at one end of the interconnecting
cable. The exchange can be made in the cable, or on the controller
board. The exchange may or may not need to be made depending on
the pin configuration, 9 or 25, of the driving DTE. The exchange may
need to be reversed if a standard 25-pin/9-pin adaptor has been added
to the driving device’s serial port. Pin-out for that arrangement is
shown below:
The rules of thumb presented on the following page may help you make
the DTE/DCE connection.
RS-232 DCE VS. DTE DECISION (OBSOLETE)
OPTION I: If the controlling RS232 device communicates over a 25-
pin serial port:
1. Configure the Control Interface Module as a DTE.
2. Use a 9-pin to 9-pin cable with no connection exchange.
3. Connect the cable to the driving, 25-pin port using a common 25-
pin/9-pin adaptor such as that used to connect a mouse to a computer’s
serial port. The adaptor swaps the connections.