The CT3IP is a fixed-configuration interface processor based on the second-generation Versatile Interface Processor (VIP2). The CT3IP has four T1 connections via DB-15 connectors and one DS-3 connection via BNC connectors. It operates on any Cisco 7500 series router or any Cisco 7000 series router equipped with an RSP7000 processor and an RSP7000CI chassis interface.Each DS-3 interface can provide up to 28 T1 channels (a single T3 group). Each channel is presented to the system as a serial interface that can be configured individually. The CT3IP can transmit and receive data bidirectionally at the T1 rate of 1.536 Mbps. The individual T1 connections use 100-ohm, twisted-pair, serial cables to external channel service units (CSUs) or to a MultiChannel Interface Processor (MIP) for subsequent channelization to 24 DS0 channels per T1. For wide-area networking, the CT3IP can function as a concentrator for a remote site. The T3 connection, provided by way of two female BNC connections for transmit (TX) and receive (RX), has an impedance of 75 ohms.