Realport Protocol - Digi PortServer/8 User Manual

RealPort Protocol

RealPort is a protocol developed by Digi International that, when used in conjunction with device
driver software on a host operating system, allows ports on the PortServer to be used as if they
were connected directly to the host system. For instance, one advantage the RealPort protocol has
over traditional TCP/IP protocols such as telnet is the host operating system can directly change
port parameters, such as baud rate, hardware flow control and software flow control using exactly
the same method used to change these settings on a local port. The ports on the PortServer may
be split among hosts; one host can use the odd-numbered ports while another is using the even
numbered ports. There is even a mechanism in place that allows one host to handle incoming
modem calls on a port, while allowing other hosts to place outgoing calls if there is no current
incoming call. (This must be supported by the host driver software.)
You must have the correct driver(s) for your host operating system(s) to take advantage of

RealPort protocol.

The device type ( set port dev= type) must be set properly for ports that are going to be used
with RealPort protocol. Ports that are to be used with three-wire connections (that do not need
modem signals) should have the device type set to prn . (However, the RealPort driver will see
the actual state of the modem signals regardless of the device type setting.) Ports that are to be
used with modems should have the device type set to mout if they are to be used exclusively for
RealPort connections, or set to mio if you want incoming calls to go directly to the PortServer's
normal login interface. Other connections that need modem signals should have the device type
set to host . All of these device types except for prn will ensure that RTS and DTR modem
signals go low and stay low for at least two seconds between connections, to allow modems and
other devices to reset properly.
Device types of term or min should not be used for RealPort devices.
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