Equipment Aspects of Packaged N2 Carrier System Terminals

The N2 carrier system provides twelve two-way message, program or narrow-band data channels over two pairs of a single toll or exchange plant cable. Occasionally, a two-way wideband channel for 40.8-kilobit data will be used in lieu of six narrow-band channels. Like the earlier N1 carrier system, double-sideband transmitted carrier signals in the 36- to 268-kc frequency band are used with repeaters at intervals up to eight miles, depending on the type of cable. This paper describes the operational, functional, and mechanical aspects of N2 carrier terminals packaged to include not only the carrier circuits but also the signaling, circuit conditioning, patching and monitoring circuits required for the complete channels derived from the N2 system. Transmission performance, ease of maintenance and economy are optimized by the use of a packaged terminal framework containing mounting shelves, connectors and shop wiring such 787 788 T H E - B E L L SYSTEM TECHNICAL J O U R N A L , MAY 1905 48