Cisco offers a variety of connectivity, expansion and upgrade modules and cards to accommodate the customer specific needs. Cisco's components are easily and inexpensively upgradeable as customer requirements change.The PA-MC-T3 is a single-width port adapter that provides one T3 interface connection using BNC connectors. The interface can provide up to 28 T1 lines (a single T3 group). Each T1 line is presented to the system as a serial interface that can be configured individually. The PA-MC-T3 has one channelized T3 high-speed serial interface that provides access to services at T1 (1.544 Mb) data rates, transferring data bidirectionally. This port adapter divides the T3 signal stream into 28 T1 lines that can be further divided into the 64 kbps level, up to a total of 128 channels.