The connection between the Legecy Base and TMCC Command Base has a way of slowing Cab1 responses. The original Command base has to be installed as has been mentioned. Effectively the Cab1 only talks to the originial Command Base, which talks to the Legecy Base, via the "Y" cable connection, which then talks to the engine via track antenna. The added link slows the process some. The Legecy "Y" cable is well marked for the connection and still allows for accessory connection.