Rick, Z I've just answered my own question by reading the occam3 draft manual. > CHAN TYPE requires the RECORD keyword in the same way that DATA TYPE > does. That suits my craving for orthogonality :-) Oops! Guess I should have read it as well ... where is my copy?!! Meanwhile: CHAN TYPE COMMS RECORD CHAN OF REQUEST request: CHAN OF REPLY reply: : Apologies, Peter.