The port file tells uucico about the available ports. These may be modem ports, but other types such as direct serial lines and TCP sockets are supported as well.
Like the sys file, port consists of separate entries starting with the keyword port, followed by the port name. This name may be used by in the sys file's port statement. The name need not be unique; if there are several ports with the same name, uucico will try each in turn until it finds one that is not currently being used.
The port command should be immediately followed by the type statement that describes what type of port is described. Valid types are modem, direct for direct connections, and tcp for TCP sockets. If the port command is missing, the port type defaults to modem.
In this section, we will cover only modem ports; TCP ports and direct lines are discussed in a later section.
In the case of a modem device, the port entry also determines what type of modem is connected to the port. Different types of modems have to be configured differently. Even modems that claim to be Hayes-compatible needn't be really compatible with each other. Therefore, you have to tell uucico how to initialize the modem and how to make it dial the desired number. Taylor UUCP keeps the descriptions of all dialers in a file named dial. To use any of these, you have to specify the dialer's name using the dialer command.
Sometimes, you will want to use a modem in different ways, depending on which system you call. For instance, some older modems don't understand when a high-speed modem attempts to connect at 14400bps; they simply drop the line instead of negotiating a connect at, say, 9600bps. When you know site drop uses such a dumb modem, you have to set up your modem differently when calling them. For this, you need an additional port entry in the port file that specifies a different dialer. Now you can give the new port a different name, such as serial1-slow, and use the port directive in drop system entry in sys.
A better way is to distinguish the ports by the speeds they support. For instance, the two port entries for the above situation may look like this:
The system entry for site drop would now give serial1 as port name, but request to use it at 9600bps only. uucico will then automatically use the second port entry. All remaining sites that have a speed of 38400bps in the system entry will be called using the first port entry.