OK. I changed the busy setting and my Kenwood now connects ... but the number of retries makes data very slow.
A 'quirk' of Kenwood radios is that during a data transmission the microphone remains active having the potential to corrupt data in a noisy environment - please remove the microphone when sending data.
Location
Nexion Solutions Unit 1, 53 Boyland Avenue, Coopers Plains, 4108 Queensland Australia