Provides dual (T1 or PRI circuits) the IP400 Office PRI card provides dual primary rate trunk interfaces. The PRI is available as T1, E1 or E1R2MFC depending on the market. Its is only supported on the IP412 and in slot A of the IP406.T1 trunk cards incorporate an integrated CSU/DSU, eliminating the need for an external unit.
The CSU function allows the trunk to be put in loop-back mode for testing purposes. This can be set manually, using the monitor application, or automatically from a Central Office sending a Line Loop Back (LLB) pattern. The DSU function allows the T1 trunk to be shared between data and voice services.