// 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_.

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* 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.

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NOTE: A special value of *USB* is available for custom USB devices
      like those used by some SDR kits. This is not the same as the 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.

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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).

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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.)