8 FSU User Manual 61200.130L1-1Chapter 2. InstallationDCE ConnectorThe connector labeled DCE provides connection to an externalDSU/CSU. The pinouts for this connector are shown in theappendix Pinouts.The connection between the FSU and an external DSU is a directconnection. When connecting to an external DSU, the FSU emulatesan externally timed DTE interface connected directly to the DCEinterface of the external device.DTE ConnectorsDTE devices are connected to the DTE connectors using either anRS-232 DTE cable or a CCITT V.35 DTE adapter cable. Themaximum cable lengths recommended are 50 feet for the RS-232and 100 feet for the CCITT V.35. The pin assignments are listedin the appendix Pinouts.The V.35 adapter cable is recommended for use with data ratesabove 19.2 kbps. A low capacitance RS-232 cable works up to 56kbps. The DTE ports are configured through the front panel orthe VT 100 control port. The DTE ports can operate in asynchro-nous or synchronous modes.Main Telco ConnectorThe Main connector is an eight-position modular jack whichprovides connection to the dedicated (DDS) network. See theappendix Pinouts for the Main connector's pin assignments.Backup ConnectorThe eight-position modular jack labeled BACKUP is provided toallow future enhancements to the FSU (dial backup options).With the dial backup option installed, this connector will pro-vide connection to the switched telco circuit.
