PA-2JT2 is a port adapter used on the VIP2 in the Cisco 7500 series routers, and in Cisco 7000 series routers using the RSP7000 and RSP7000CI.Each JT2 interface port consists of two coaxial, BNC connectors. The adapter provides two data terminal equipment (DTE), synchronous serial interface ports, which are compatible with and specified by G.703a, and which permit Cisco 7000 series and Cisco 7500 series routers to communicate over a High Speed Digital 6.3 MHz (HSD 6.3) leased line service (specified in ITU Recommendation G.704). It uses bipolar with 8-zero substitution (B8ZS) encoding and supports cyclic redundancy check (CRC), operates at 6.312 Mbps, with 50-percent pulse-width B8Zs encoding. The device provides an internal fixed clock rate on each JT2 interface port of 6.144 Mbps (not configurable). The JT2 interfaces automatically use the internal clock for data transmission if no external clock is detected. When a JT2 interface is configured with the clock source internal command, external devices will return this clock on the JT2 interface's receive line; therefore, all clocking is properly synchronized. Provides the functions needed to frame a wideband payload to ITU G.704 and the Nippon Telegram and Telephone Corporation (NTT)-specified 6.144-Mbps frame format.