TACS
Total Access Communications System. Original analogue standard used in the UK. See ETACS.

Talktime
The number of minutes of continuous speech that a freshly charged battery will allow you to make on a cellphone.

TDMA
Time Division Multiple Access. Type of processing system used by digital mobile phones that allows several handsets in the same area to use the same frequency. Each conversation is allocated its own time slot – so that you only hear the conversation for the fraction of each second. However, as the interval between each burst of signal is small, these gaps are imperceptible to the two people having the conversation. Both GSM and DECT use TDMA to ensure efficient use of allotted frequencies.

Transportable
The transportable cellular phone is a standard mobile phone that can be removed from the vehicle and used by itself with an attached battery pack. The entire unit is generally mounted or built into a custom carrying case to make it easy to carry. Although technically "portable," the transportable should not be confused with smaller, one-piece cellular phones.

Travel charger
Small charger that connects direct to a socket in the phone. Unlike with a desktop charger, there is no cradle to support the handset.

Tri-band
Triple-band phones are capable of operating on three GSM frequency bands – the GSM 900 and GSM 1800 frequencies used in over 100 countries worldwide plus the GSM 1900 frequency band that’s increasingly being adopted in America.

Trickle charger
A charger which takes eight or more hours to replenish the battery. Better for longevity of battery, but less convenient than fast chargers.

T9
Predictive text inputting system designed (by Tegic) to make text message writing easier. Instead of having to select letters individually by pressing each key numerous times, mobiles with T9 software ‘guess’ what you’re writing as you go along, reducing the number of key presses required.