If you use a serial cable or USB to serial why do you need the Lionel Y connector?
Ken M
The Lionel Y connector cable is for having a serial to go to the computer and a connection to go to the Powermaster Bridge. That's the only use for it. The end that goes to the Powermaster Bridge is a totally different set of pin connections than the normal serial pin out.
cjack, the "Y" supplied with the Legacy system is more commonly used to hook a TMCC Base to the Legacy Base, hence the label "Command Base" on the male 9-pin connector. The connections at the 9-pin "Command Base" connector are still pins 2, 3 and 5. Those pins just feed into different pins at the male Legacy Base - pins 4, 1 and 5.
Perhaps you are referring to a different "Y" cable?