Rev. B 7-34 HMXMC00101331-Mar-067.10 SERIAL COMMUNICATIONS PORTS, CONTINUED7.10.2 Subrack PortPort(02) is defined as a subrack communications port. As several subrack identitieshave been specified against this port, it is assumed the MX18 external port expander isconnected. Only data commands for the specified subrack identities will be past out ofthis port. The baud rate has been set to 19.2K baud with an RS-232 format of; 7 databits, Even parity, 1 stop bit and Xon/Xoff handshaking enabled. The port stay alive (A)flag is also set for this port. Every port flagged for STAY-ALIVE will have an ACK ($06)character written out that port every two seconds. This is used by the MX18 externalport expander to validate continuous system communications on that port.7.10.3 Network PortPort(03) is defined as a network communications port. It has been given a single videosystem network node number of (02). Only network data for that specific video systemwill be written out of that port. This port does NOT carry subrack or keyboard datamessages. It is important that equipment is connected to the correctly definedcommunications port.Network ports are also used for connecting the MAX GRAPHIC PLATFORM (MGP) to theMAXPRO-Net video system.7.10.4 High-Level PortPort (04) is defined as a high-level communications port. High-Level communicationsports are used for communicating status messages between an external alarmmanagement system and the MAXPRO-Net video system. In the example high-levelsubrack identity of (H99) has been allocated against this port.High-level communications ports are also used for connecting hardware MIMIC panelsto the MAXPRO-Net video system.7.10.5 Printer PortPort (05) is defined as a serial printer port. The MAXPRO-Net usually supports a parallelprinter interface port. In some cases it is necessary to convert this printer data into RS-232 serial data for display onto a CRT TERMINAL. All printer output will be automaticallyre-directed to the defined RS-232 serial printer port. The parallel printer port becomesdisabled.WARNING: Only ONE printer (PRT) port can be definedin the communications port table. If additional RS-232printers are required, AUX auxiliary ports need to bedefined.
