// Status=review

_WSJT-X_ offers CAT (Computer Aided Transceiver) control of relevant
features of most modern transceivers.  To configure the program for
your radio, select the *Radio* tab.

image::RadioTab.png[align="center",alt="Radio Tab"]

* Select your radio type from the drop-down list labeled *Rig*, or
  *None* if you do not wish to use CAT control.

** Alternatively, if you have configured your station for control by
   *DX Lab Suite Commander*, *Flrig*, *Ham Radio Deluxe*, *Hamlib NET
   rigctl*, or *Omni-Rig*, you may select one of those program names
   from the *Rig* list.  In these cases the entry field immediately
   under _CAT Control_ will be relabeled as *Network Server*.  Leave
   this field blank to access the default instance of your control
   program, running on the same computer. If the control program runs
   on a different computer and/or port, specify it here.  Hover the
   mouse pointer over the entry field to see the required formatting
   details.

** Select *Omni-Rig Rig 1* or *Omni-Rig Rig 2* to connect to an
   _Omni-Rig_ server installed on the same computer. _Omni-Rig_ will
   be started automatically by _WSJT-X_.

+

* Set *Poll Interval* to the desired interval for _WSJT-X_ to query
  your radio.  For most radios a small number (say, 1 – 3 s) is
  suitable.

* _CAT Control_: To have _WSJT-X_ control the radio directly rather
  than though another program, make the following settings:

** Select the *Serial Port* or *Network Server* including the service
  port number used to communicate with your radio.

+

NOTE: A special value of *USB* is available for custom USB devices
      like those used by some SDR kits. This is not the same a virtual
      serial port provided by USB connected transceivers and CAT
      interfaces, for those use the COM or serial port name that
      refers to them.

** _Serial Port Parameters_: Set values for *Baud Rate*, *Data Bits*,
  *Stop Bits*, and *Handshake* method.  Consult your radio's user
  *guide for the proper parameter values.

+

NOTE: CAT interfaces that require handshaking will be non-responsive
      until the correct *Handshake* setting is applied.

** _Force Control Lines_: A few station setups require the CAT serial
  port’s *RTS* and/or *DTR* control lines to be forced high or
  low. Check these boxes *only* if you are sure they are needed (for
  example, to power the radio serial interface).

* _PTT Method_: select *VOX*, *CAT*, *DTR*, or *RTS* as the desired
  method for T/R switching.  If your choice is *DTR* or *RTS*, select
  the desired serial port (which may be the same one as used for CAT
  control).

+

NOTE: When using a proxy application for rig control, *CAT* is usually
      the correct option for _PTT Method_ assuming the proxy
      application is capable of keying your transceiver independently.

* _Transmit Audio Source_: some radios permit you to choose the
  connector that will accept Tx audio.  If this choice is enabled,
  select *Rear/Data* or *Front/Mic*.

* _Mode_: _WSJT-X_ uses upper sideband mode for both transmitting and
  receiving.  Select *USB*, or choose *Data/Pkt* if your radio offers
  such an option and uses it to enable the rear-panel audio line
  input.  Some radios also offer wider and/or flatter passbands when
  set to *Data/Pkt* mode.  Select *None* if you do not want _WSJT-X_
  to change the radio's Mode setting.

* _Split Operation_: Significant advantages result from using *Split*
  mode (separate VFOs for Rx and Tx) if your radio supports it.  If it
  does not, _WSJT-X_ can emulate such behavior.  Either method will
  result in a cleaner transmitted signal, by keeping the Tx audio
  always in the range 1500 to 2000 Hz so that audio harmonics cannot
  pass through the Tx sideband filter.  Select *Rig* to use the
  radio's Split mode, or *Fake It* to have _WSJT-X_ adjust the VFO
  frequency as needed, when T/R switching occurs.  Choose *None* if
  you do not wish to use split operation.

When all required settings have been made, click *Test CAT* to test
communication between _WSJT-X_ and your radio.  The button should turn
green to indicate that proper communication has been established.
Failure of the CAT-control test turns the button red and displays an
error message.  After a successful CAT test, toggle the *Test PTT*
button to confirm that your selected method of T/R control is working
properly, the button turns red if the rig has been successfully
keyed. (If you selected *VOX* for _PTT Method_, you can test T/R
switching later by using the *Tune* button on the main window.)