This is a keyer selector designed for situations where more than one operator is on a band. It also provides an interlock which allows a multiplier station to be used in M/2 operations.
The unit is designed primarily for CW keyer selection but it can also be used for phone PTT selection or for mixed mode where one radio is used for CW and another for SSB.
Figure 1 shows the Keyer Selector connected in a multi-operator two radio (MO2R) configuration. Amplifiers and antenna switching are not shown. Each operator has a computer and a keyer. Either operator can transmit through one or both radios.