Basic Rate

• The total data rate across this interface 144 000 bits per second.
• This bit rate was chosen because the wiring already installed by the telephone companies under the streets can carry baseband (digital) transmission at this speed.

Primary Rate

• The total data rate across this type of interface is 2 048 000 bits per second (2Mbits per second) in Europe. In North America and some other countries the total data rate is 1 536 000 bits per second (1.5Mbits per second)
• This kind of access requires the installation of a high-speed line to the customer premises.

Normally, Basic Rate would be for domestic use, telecommuters or smaller remote offices. Primary Rate would typically be used for large remote access servers, fax servers or PBXs in medium sized or large offices. For instance, most ISPs (Internet Services Providers) use PRI lines to provide dial-in analogue and ISDN connections for their subscribers.