The "Standard" TV/Cable switch is a wall plate with an ON.OFF switch or buttonm an LED a 12 volt outlet and an antenna connection.
THis is the "SOurce" Switch switching between, nornmally, Cable and Over the air antenna (ON = Antenna) It also provides power to the amplifier inside the antenna and its a splitter going to your TV-2 (and optionally TV-3)
THe dual jack is most likely in the CABLE line
Park cable lead goes to ONE of those two jacks the other goes on to the switchm Back in the days of SD Satellite receivers with Coax out you could remove that jumper and replace it with the Sat Receiver.
Today you can use it for a cable decryptor box rented from the camnpground if the cable system is encrypted.