OK Thankyou for your help so far, the baud rate for mode 2 CI-V was set at 19200, reducing this to 9600 seems to have stopped the mode changing, however when using WSJT-X with LOG4OM through omnirig (which is set at 19200 as is the silicon labs usb port as is the baud rate set in the 7100) I randomly have the TX stick on after a FT8 transmission, which unsticks itself after the next TX. I have reduced the power out to 0 and this still occurs so is not an RF problem. If I disconnect the serial cable from the CI-V interface I loose any connectivity with the USB ci-v, but if I disconnect the cable between the remote on the radio and the ci-v interface the TX never sticks on, but obviously the antenna switch stops working automatically. Unlike newer Icom radios there is no unlink setting in the 7100. Do you think I have a setting wrong in the 1258 boxes, should the baud rates be the same for both CI-V circuits.