fcd-2 has a rs-232 asynchronous dce port, designated sp and terminated in 9-pin, d-type female connector. the supervisory port continuously monitors the incoming data stream and will immediately respond to any input string received through this port.

    the supervision terminal can be connected either directly to the fcd-2 supervisory port, or through a modem or any other type of full-duplex data link.

    the fcd-2 supervisory port interface type must be set in accordance with the connection method (see table 3-5).

    1 dce for direct connection. since terminals usually have dte interfaces, in this case the connection to the port is made by means of a straight-through cable.

    2 dte for connection through a modem or data link. in this case, you need a cross-over cable (also called modem cable).

    fcd-2 can communicate with the supervision terminal at rates of 0.3, 1.2, 2.4, 4.8 or 9.6 kbps. the word format consists of one stop bit, and 7 or 8 data bits. parity can be odd, even or disabled.

    the communication interfaces of the terminal and fcd-2 must be configured for operation with the same parameters.

    fcd-2 supports two types of modems:

    3 dial-up hayestm compatible modems. fcd-2 has only call-in capability, that is, fcd-2 will recognize and answer incoming calls from the supervision terminal to permit starting a configuration session.

    4 multidrop modems. for multidrop operation, each fcd-2 can be assigned a node address in the range of 1 through 255. assigning address 0 to fcd-2 means that it will accept and answer any message: this is not permitted in multidrop operation. address 0 is however recommended for use with both point-to-point and dial-up modes.

    the relevant configuration parameters are described in section 3.4. instructions for configuring the fcd-2 supervisory port appear in section 3.6.

    supervisory port handshaking protocol

    the handshaking between fcd-2 and the supervision terminal uses the control lines in the fcd-2 sp connector. the control lines being used in each mode and the direction of the control signals is detailed in the following chart.

    data terminal ready (dtr)

    the terminal sets the dtr line on (active) to gain control over the fcd-2 and start a configuration/monitoring session.