Primary Rate Interface ISDN (PRI-ISDN)

Definition of Primary Rate Interface ISDN (PRI-ISDN) in Network Encyclopedia.

What is Primary Rate Interface ISDN (PRI-ISDN)?

PRI-ISDN is a standard form of communication on Integrated Services Digital Network (ISDN) communication systems. Primary Rate Interface ISDN (PRI-ISDN) connections consist of 24 digital channels divided between 23 B channels and a single D channel.

The B channels carry the voice or data between the customer premises and the telco’s central office (CO), while the D channel is used for establishing connections and signaling.

PRI-ISDN is often referred to as 23B+D because of the channels that it uses.


The bandwidth of each B channel and of the single D channel is 64 Kbps, so the total bandwidth of PRI-ISDN is 1.544 Mbps, which is identical to that of a T1 circuit. By using the bonding protocol, the 23 B channels can be combined to form a single 1.472-Mbps data channel. The European version of PRI-ISDN uses 31 B channels and one D channel, providing the bandwidth of an E1 circuit.

See also:


Articles posted after being checked by editors.

Recent Content

link to Public Key Infrastructure (PKI)

Public Key Infrastructure (PKI)

Public Key Infrastructure, also known as PKI, is a set of services that support the use of public-key cryptography in a corporate or public setting. A public key infrastructure (PKI) enables key pairs to be generated, securely stored, and securely transmitted to users so that users can send encrypted transmissions and digital signatures over distrusted public networks such as the Internet.
link to Digital Signature

Digital Signature

Digital Signature is an electronic signature that you can use to sign a document being transmitted by electronic means such as e-mail. Digital signatures validate the identity of the sender and ensure that the document they are attached to has not been altered by unauthorized parties during the transmission.