support for TRX that feedback the tx signal to rx

configname: CONFIG_SCC_TRXECHO

Linux Kernel Configuration
└─>Networking support
└─>Amateur Radio support
└─>AX.25 network device drivers
└─>support for TRX that feedback the tx signal to rx
In linux kernel since version 2.6.12  
Some transmitters feed the transmitted signal back to the receive
line. Say Y here to foil this by explicitly disabling the receiver
during data transmission.

If in doubt, say Y.