An interface circuit and method for interfacing received digital signals, relative to a first ground potential, for transmission on the bus, relative to a second ground potential. The hitch pin is comprised of shaft with a locking member on one end and a handle and weight on the other end and a spring and retainers to keep the hitch pin in place. The printed board is permanently fixed to the first body part. A list of conversations to which the various messages belong is displayed in an order determined in accordance with other predefined criteria, such as ordering the conversations by the last date a message was received in a particular conversation.