A POS-based checkoutscale system having a bar code symbol reading subsystem for reading bar code symbols on products being purchased at a retail POS station, and a produce weigh scale having a weigh scale assembly for weighing one or more produce items on a weigh platter during produce weighing operations carried out at the time of checkout at said retail POS station. The TR switch comprises 1) a first circulator having a first port for receiving a transmit signal from the transceiver during transmit mode, a second port for sending the transmit signal to the antenna during transmit mode and receiving a received signal from the antenna during receive mode, and a third port for sending the received signal towards the transceiver during receive mode. The shield provides sufficient rigidity for the CT scanner subsystem.