Central office telephone equipment serving subscribers at one location on a private automatic branch exchange basis. The system allows such servicesas direct inward dialing,direct distance dialing,and console switchboards.

• 中央局的电话设备，以用户专用自动交换机方式为某一地区的用户服务。该系统允许直接内部拨号、长途直接拨号以及控制台交换转接等。