The MBTA says cellphone service should be available on most Green and Blue lines by the end of the year.
Depending on carrier, cell service is already available on the Red and Orange lines.
MBTA spokesman Joe Pesaturo said customers should remember to be considerate.
"It's also important to remember that some customers on the subway or your bus might not want to hear every element of your conversation with your friend or your relative while you're on the phone," he said.
Pesaturo said the MBTA could bring in $5 million under a 15-year contract to bring cell service to the T.
This program aired on October 5, 2011. The audio for this program is not available.