Pin AssignmentsD-53170-A2-GB20-20 December 1996COM Port InterfaceThe COM port connects to a PC for front panelemulation, to an ASCII terminal or printer for alarms, to anetwork device (e.g., a router) for SNMP applications, tothe SNMP LAN Adapter for SNMP applications, or toanother E1 DSU/CSU’s AUX port for daisy chainconnectivity. (The SNMP LAN Adapter includes thecable that is needed to attach it to the E1 DSU/CSU.)The COM port connector is an 8-position keyed modularconnector (Table D-4). The data signals on this port arereferenced to a DTE interface.The COM port-to-PC cable is shown in Figure D-3 andthe COM port-to-terminal/printer cable is shown inFigure D-4.NOTEFor daisy-chaining an AUX portto a COM port, a customersupplied, 8-pin-to-8-pin, straight-through cable is required andthe appropriate configurationoptions (Com Use and Aux Use)must be set to Daisy. Wheneverthe cable is connected ordisconnected, you shouldchange the Daisy selection toensure that the correctparameters have beennegotiated for the link layer.Table D-4COM Port ConnectorSignal Direction Pin NumberDCE Transmit Clock From DSU/CSU 1DCE Receive Data From DSU/CSU 2Signal Ground — 3DCE Transmit Data To DSU/CSU 4DCE Data Terminal Ready To DSU/CSU 5DCE Carrier Detect From DSU/CSU 6DCE Request-to-Send To DSU/CSU 7DCE Receive Clock From DSU/CSU 8
