A network device used by telecom carriers and large enterprises to switch and multiplex low-speed voice and data signals onto high-speed lines and vice versa. It is typically used to aggregate several T1 lines into a higher-speed electrical or optical line as well as to distribute signals to various destinations; for example, voice and data traffic may arrive at the cross-connect on the same facility, but be destined for different carriers. Voice traffic would be transmitted out one port, while data traffic goes out another. Cross-connects come large and small, handling only a few ports up to a few thousand. Narrowband, wideband and broadband cross-connects support channels down to DS0, DS1 and DS3 respectively. Used With Telephone Switches Digital cross-connects (DCSs) are widely used in conjunction with central office telephone switches and may be installed both before and/or after the switch. Cross-connections are established via an administrative process and are semi-permanent, whereas the telephone switch dynamically picks up dialing instructions and routes calls based on telephone number. See optical cross-connect.