Direct links 

You can create a direct link to another computer by running RS-232 cables between serial ports on the two machines. Direct links are useful when two computers communicate regularly and are physically close—within 50 feet of each other. You can use a limited-distance modem to increase this distance somewhat.

Telephone lines 

Using an automatic call unit (ACU), such as a high-speed modem, your machine can communicate with other computers over standard phone lines. The modem dials the telephone number that is requested by UUCP. The recipient machine must have a modem capable of answering incoming calls.

Network 

UUCP can also communicate over a network that runs TCP/IP or an other protocol family. After your computer has been established as a host on a network, it can contact any other host that is connected to the network.

uucico

Selects the device that is used for the link, establishes the link to the remote computer, and performs the required login sequence and permission checks. Also, uucico transfers data and execute files, logs results, and notifies the user by mail of transfer completions. uucico acts as the “login shell” for UUCP login accounts. When the local uucico daemon calls a remote machine, it communicates directly with the remote uucico daemon during the session.

After all the required files have been created, uucp, uuto, and uux programs execute the uucico daemon to contact the remote computer. uusched and Uutry all execute uucico. See the uucico(1M) man page for details.

uuxqt

Executes remote execution requests. This daemon searches the spool directory for execute files (always named X.file) that have been sent from a remote computer. When an X.file file is found, uuxqt opens it to get the list of data files that are required for the execution. uuxqt then checks to see if the required data files are available and accessible. If the files are available, uuxqt checks the Permissions file to verify that it has permission to execute the requested command. The uuxqt daemon is executed by the uudemon.hour shell script, which is started by cron. See the uuxqt(1M) man page for details.

uusched

Schedules the queued work in the spool directory. uusched is initially run at boot time by the uudemon.hour shell script, which is started by cron. See the uusched(1M) man page for details. Before starting the uucico daemon, uusched randomizes the order in which remote computers are called.

in.uucpd

Supports UUCP connections over networks. The inetd on the remote host invokes in.uucpd whenever a UUCP connection is established. uucpd then prompts for a login name. uucico on the calling host must respond with a login name. in.uucpd then prompts for a password, unless one is not required. See the in.uucpd(1M) man page for details.

uulog

Displays the contents of a specified computer's log files. Log files are created for each remote computer with which your machine communicates. The log files record each use of uucp, uuto, and uux. See the uucp(1C) man page for details.

uucleanup

Cleans up the spool directory. uucleanup is normally executed from the uudemon.cleanup shell script, which is started by cron. See the uucleanup(1M) man page for details.

Uutry

Tests call-processing capabilities and does moderate debugging. Uutry invokes the uucico daemon to establish a communication link between your machine and the remote computer you specify. See the Uutry(1M) man page for details.

uucheck

Checks for the presence of UUCP directories, programs, and support files. uucheck can also check certain parts of the /etc/uucp/Permissions file for obvious syntactic errors. See the uucheck(1M) man page for details.

cu

Connects your machine to a remote computer so that you can log in to both machines at the same time. cu enables you to transfer files or execute commands on either machine without dropping the initial link. See the cu(1C) man page for details.

uucp

Lets you copy a file from one machine to another. uucp creates work files and data files, queues the job for transfer, and calls the uucico daemon, which in turn attempts to contact the remote computer. See the uucp(1C) man page for details.

uuto

Copies files from the local machine to the public spool directory /var/spool/uucppublic/receive on the remote machine. Unlike uucp, which lets you copy a file to any accessible directory on the remote machine, uuto places the file in an appropriate spool directory and tells the remote user to pick it up with uupick. See the uuto(1C) man page for details.

uupick

Retrieves files in /var/spool/uucppublic/receive when files are transferred to a computer by using uuto. See the uuto(1C) man page.

uux

Creates the work, data, and execute files that are needed to execute commands on a remote machine. See the uux(1C) man page for details.

uustat

Displays the status of requested transfers (uucp, uuto, or uux). uustat also provides a means of controlling queued transfers. See the uustat(1C) man page for details.

Config

Contains a list of variable parameters. You can manually set these parameters to configure the network.

Devconfig

Used to configure network communications.

Devices

Used to configure network communications.

Dialcodes

Contains dial-code abbreviations that can be used in the phone number field of Systems file entries. Though not required, Dialcodes can be used by asppp as well as UUCP.

Dialers

Contains character strings that are required to negotiate with modems to establish connections with remote computers. Dialers is used by asppp as well as UUCP.

Grades

Defines job grades, and the permissions that are associated with each job grade, which users can specify to queue jobs to a remote computer.

Limits

Defines the maximum number of simultaneous uucicos, uuxqts, and uuscheds that are permitted on your machine.

Permissions

Defines the level of access that is granted to remote hosts that attempt to transfer files or execute commands on your machine.

Poll

Defines machines that are to be polled by your system and when they are polled.

Sysfiles

Assigns different or multiple files to be used by uucico and cu as Systems, Devices, and Dialers files.

Sysname

Enables you to define a unique UUCP name for a machine, in addition to its TCP/IP host name.

Systems

Contains information that is needed by the uucico daemon, cu, and asppp to establish a link to a remote computer. This information includes the name of the remote host, the name of the connecting device associated with the remote host, time when the host can be reached, telephone number, login ID, and password.