What are “T-Port” roms?

[ensbana]

Sometimes when I look for roms online, I see there is a “T-Port” version. Anyone knows what that means?

[ulaoulao]

T-Port means translated port.

[Rosenivy]

The T-port valve is basically the L-port valve, but the ball is drilled all the way through in one direction. So the drilling of the ball resembles the shape of the letter T. With a L-port, the middle port is the common port, and with a T-port, one of the side ports is the common port.