PRACH and CPRACH are used by MS to initiate uplink transfer for sending data or signalling information. Packet Access burst and Extended Packet Access burst are used on PRACH. Extended Packet Access burst is used on CPRACH.

PPCH and CPPCH are used to page an MS prior to downlink packet transfer. PPCH and CPPCH use paging groups in order to allow usage of DRX mode. PPCH can be used for paging of both circuit switched and packet data services. The paging for circuit switched services on PPCH is applicable for class A and B GPRS MSs in Network operation mode I, see TS 23.060.

PAGCH and CPAGCH are used in the packet transfer establishment phase to send resource assignment to an MS prior to packet transfer.

PDTCH is a channel allocated for data transfer. It is temporarily dedicated to one MS or to a group of MSs in the case of p-t-m transmission. In the multislot operation, one MS or a group of MSs may use multiple PDTCHs in parallel for individual packet transfer. All packet data traffic channels are uni-directional, either uplink (PDTCH/U), for a mobile originated packet transfer or downlink (PDTCH/D) for a mobile terminated packet transfer. A packet data traffic channel supporting operation in extended coverage is referred to as Extended Coverage PDTCH (EC-PDTCH).

PACCH conveys signalling information related to a given MS. The signalling information includes e.g. acknowledgements and power control information. PACCH carries also resource assignment and reassignment messages, comprising the assignment of a capacity for PDTCH(s) and for further occurrences of PACCH. The PACCH shares resources with PDTCHs, that are currently assigned to one MS. Additionally, a MS that is currently involved in packet transfer, can be paged for circuit switched services on PACCH. A Packet Associated Control Channel supporting operation in extended coverage is referred to as Extended Coverage PACCH (EC-PACCH). The EC-PACCH shall not be used to page a MS in extended coverage for circuit switched services.

PTCCH/U is used to transmit random access burst to allow estimation of the timing advance for one MS in packet transfer mode. PTCCH/U shall not be used for DTM. PTCCH/U shall not be used for a mobile station in EC operation.

PTCCH/D is used to transmit timing advance information updates to several MS. One PTCCH/D is paired with several PTCCH/U's. PTCCH/D shall be ignored by MS operating in DTM. PTCCH/D shall be ignored by a mobile station in EC operation.

The MPRACH is used by the MS during the initial counting procedure for MBMS (see TS 44.060). Packet Access burst and Extended Packet Access burst are used on MPRACH.