Traffic channels are defined for speech, and for data at the rates of 9.6kb/s, 4,8kpbs and 2.4kbps.

These may be full or half rate (except for 9.6kb/s which must be 'full rate').

In addition a number of logical signaling channels are specified. These operate at different rates, and have individual functions:

• Slow associated control channels - for control and supervisory signals associated with the traffic channels.
• Fast associated control channels - which steal time slots from the traffic allocation and are used for control requirements such as handover.
• Dedicated control channels - which are multiplexed on to a standard channel and are used for registration, location updating, authentication and call set-up.
• Broadcast control channels (down link only) - which provide the mobile stations with information such as base station identity.
• Paging channel (down link only) - which informs the mobile that the network requires to signal it.
• Random-access channel (up link only) - which is used by the mobile station to request access to the network.
• Access grant channel (clown link only) - which replies to a random access arid assigns a dedicated control channel for subsequent signaling.

• Cell Broadcast Channel (down link only) - transmits the cell broadcast information.