Cell phone service is available in all stations and also between stations while riding the subway. Wifi is also available to paying customers of various telecom companies. Some tourism websites cite Wifi available for free, but in reality this is difficult if not impossible to connect to. Both Wifi and cell signal service is available due to infrastructure installed by the individual telecom companies. These larger boxes are connected to receivers in the ceiling, usually a white color to blend in, and send the signal outside so you can complete your call uninterrupted.

Here is an example of a receiver mounted on a ceiling. As this was an underground aquarium which wants guests to view the fish, not the ceiling, the ceiling was painted black as to not distract people. As subways systems need to be bright, their ceilings are white and the receivers blend in much better there.