Primary Rate Interface (PRI) is an ISDN interface for primary rate access , which consists of a single 64-kbps D channel plus 23 (T1) or 30 (E1) B channels for voice or data.

• 主速率接口是一个适用于主速率通道的ISDN接口，它是由一个单个的64-kbps的D通道再加23个（T1）或30个（E1）语音或数据B通道构成的。