Devices File Format for BNU

Purpose

Contains information about devices on the local system that can establish a connection to a remote computer using the Basic Networking Utilities (BNU) program.

Description

The /etc/uucp/Devices file and its augmentations and alternatives specified in the /etc/uucp/ Sysfiles file contains information about the devices on the local system that can establish a connection to a remote computer using the Basic Networking Utilities (BNU) program. This file includes information for hardwired, telephone, and TCP/IP communication links.

Note: Only someone with root user authority can edit the Devices file, which is owned by the uucp login ID.

Fields in the Devices File

The Devices file must contain a description of each device on the local system that can establish a remote connection using the BNU program. Each line in the Devices file includes the following fields:

Item	Description
Type	Typically specifies the type of hardwired or automatic calling unit (ACU) device.
Line	Specifies the device name for the port.
Line2	Specifies the dialer name if the Line entry specifies an 801 dialer.
Class	Typically specifies the transmission speed.
Dialer-Token Pairs	Specifies a particular type of autodialer (modem) and the token (a defined string of characters) that is passed to the dialer. Valid entries for this field are defined in the /etc/uucp/Dialers file.

The fields appear on the line as follows:

Type Line Line2 Class Dialer-Token Pairs

Every field of a line in the Devices file must contain an entry. If a field does not apply to the particular type of device or system, use a - (minus sign) as a placeholder.

Lines in the Devices file cannot wrap. Each entry must be on only one line in the file. However, the Devices file can contain blank lines and comment lines. Comment lines begin with a # (pound sign). Blank lines are ignored.

Type Field

Enter one of the following keywords in this field:

Keyword	Explanation
ACU	Use this keyword, entered in uppercase letters, if your site connects multiple systems over the telephone network with automatic calling units (autodialers or modems).
Direct	Use this keyword, beginning with an uppercase D, if your site uses hardwired lines to connect multiple systems.
TCP	Use this keyword, in uppercase letters, if your site uses TCP/IP.
SystemName	Enter the name of a particular remote system hardwired to the local system. The SystemName keyword is the name assigned to each individual system, such as `hera`, `zeus`, or `merlin`.

This field corresponds to the Type field in the /etc/uucp/Systems file.

Line Field

The device name for the line, or port, used in the communication link is inserted here. For example, use the appropriate device name for a hardwired line, such as tty1. For a line connected to an ACU (a modem), use a device name appropriate to the dialer, such as tty1 or tty2. For a TCP connection, enter a minus sign as a placeholder.

Line2 Field

Unless you are using an 801 dialer, use a - (minus sign) in this field as a placeholder. If you are using an 801 dialer, put the device name of the 801 ACU in this field. For example, if the entry in the Type field is ACU and the Line field entry (specifying the modem) is tty1, the Line2 field entry (specifying the 801 dialer for the modem) might be tty3 or tty4.

Note: The Line2 field is used only to support older modems that require 801-type dialers. The modem is plugged into one serial port, and the 801 dialer is plugged into a separate serial port.

Class Field

For an ACU or a hardwired line, the Class field can be the speed of the device. In this case, for a hardwired line, use the transmission rate of the device connecting the two systems. For a telephone connection, use the speed at which the ACU transmits data, such as 300 or 1200 bps.

This field can also contain a letter with a speed (for example, C1200 or 1200) to differentiate between classes of dialers. For example, some offices have more than one telephone network, one for internal use and one for external communications. In such a case, it is necessary to distinguish which lines should be used for each connection.

The Class field in the Devices file is matched against the Class field in the /etc/uucp/Systems file. For example, if the Systems file entry for system hera is:

hera Any ACU 1200 3-3-5-2 ogin: nuucp ssword: oldoaktree

BNU searches for an entry in the Devices file with a Type of ACU and a Class of 1200.

Some devices can be used at several specific speeds. In this case, make multiple entries for the device, specifying each speed on a separate line in the Devices file. If BNU cannot connect at the first speed, it will try the successive speeds.

If a device can be used at any speed, type the word Any in the Class field. Note that the A in Any must be uppercase.

For a TCP/IP connection, enter a - (minus sign) as a placeholder.

Dialer-Token Pair Field

The Dialer-Token Pair field specifies a particular type of autodialer (modem) and the token (a defined string of characters) that is passed to the dialer. Valid entries for this field are defined in the /etc/uucp/Dialers file.

For a hardwired connection, enter the word direct (note the lowercase d) as the Dialer entry and leave the Token entry blank.

For a telephone connection, enter the type of dialer and the token that is passed to that modem. The Token field entry is either a telephone number or a predefined string used to reach the dialer.

For a telephone connection, enter one of the following as the Dialer field entry:

Entry	Definition
`hayes`	A Hayes dialer.
Other Dialers	Other dialers that you can specify by including the relevant information in the /etc/uucp/Dialers file.
`TCP`	A TCP/IP connection. Enter `TCP` in the Dialer field entry if you have also entered `TCP` in the Type field.

Each Dialer field entry included as part of a Dialer-Token Pair field in the Devices file has a corresponding entry in the Dialers file.

If the Token field entry represents a telephone number, enter one of the following in the Token field to specify how the BNU program should use the telephone number listed in the /etc/uucp/Systems file:

Entry	Definition
`\D`	The default token in a Dialer-Token Pair field. The `\D` token specifies that the BNU program should take the phone number listed in the /etc/uucp/Systems file and pass it to the appropriate dialer script (entry) in the /etc/uucp/Dialers file, without including a dial-code abbreviation.
`\T`	This token instructs the BNU program to process the phone number by including the data specified in the /etc/uucp/Dialcodes file. Note: If you are using dial-code abbreviations specified in the Dialcodes file for certain telephone numbers, you must enter the `\T` string as the token in those entries in the Dialers file.
blank	Leaving the Token field blank is the same as entering `\D`, so a blank is usually sufficient as a token if you have included complete telephone numbers in the /etc/uucp/Systems file. If the Token field does not represent a telephone number, enter the predefined string necessary to reach the dialer.

Examples

Setting Up Entries for Hardwired Connections

To set up a Device file entry specifying a port and a remote system, make an entry as follows:

Direct tty1 - 1200 direct
zeus tty1 - 1200 direct

The Type field lists Direct (for a direct connection) in the first part and zeus (the name of the remote system) in the second part. The local system is connected to system zeus by way of device tty1, which is listed in the Line field in both parts of the example.

The Line2 field contains actual data only when the entry specifies a certain type of telephone connection. A - (minus sign) is used as a placeholder in other types of connections, as in this example. This device transmits at a rate of 1200 bps, which is listed in the Class field in both parts of the example. The word direct in the Dialer field portion of the Dialer-Token Pair field indicates that this is a direct connection.

Setting Up Entries for Autodialer Connections

For a standard Hayes modem that can be used at only one baud rate, make an entry as follows:
```
ACU tty2 - 1200 hayes
```
The Type field is specified as ACU. The Line field is specified with the device name tty2. Because this modem is not an 801 dialer, a - (minus sign) is used as a placeholder in the Line2 field. The Class field entry is a transmission rate of 1200 baud. The Dialer field part of the Dialer-Token Pair field is specified as a hayes modem, and the Token field part is left blank.
To specify a standard Hayes modem that can be used at different baud rates, make an entry as follows:
```
ACU tty3 - 1200 hayes
ACU tty3 - 300 hayes
```
These two lines specify the same modem, a hayes, which can be used at either 1200 or 300 baud, as specified in the Class field. The modem is connected to a device named tty3 (the Line field), and the Line2 field contains the - (minus sign) placeholder. The Dialer field part of the Dialer-Token Pair field is specified as a hayes modem, and the Token field is left blank.
To specify a standard Hayes modem that can be used at any baud rate, make an entry as follows:
```
ACU tty2 - Any hayes
```
These two lines specify a hayes modem that can be used at any baud rate, as specified by the word Any entered in the Class field. Note that the word Any must be entered with an uppercase A.
To specify a connection using a standard 801 dialer, make an entry as follows:
```
ACU tty4 tty5 1200 801
ACU tty6 tty7 300 801
```
In these entries, the ACU entries are connected to devices named tty4 and tty6, specified in the Line field. In both cases, there is an entry in the Line2 field because a standard 801 autodialer is specified in the Dialer-Token Pair field. Because 801 is specified as the dialer in these two examples, the Line2 field must contain the device names of the 801 ACUs. The Class field entry specifies a transmission rate of 1200 baud for the first example and 300 for the second. The Token field part of the Dialer-Token Pair field is blank.

Setting Up the Entry for Use with TCP/IP

If your site is using the TCP/IP system, enter the following in the Devices file:

TCP - - - TCP

TCP is specified in the Type field. minus signs are used as placeholders in the Line, Line2, and Class fields. TCP is specified as the Dialer field entry, with the Token entry left blank.

Setting Up Entries for Both Local and Remote Systems

The following examples illustrate the entries needed in the Devices file for both local and remote systems in order for the two systems to communicate using the BNU program.

To configure a hardwired connection, note the following information.
The following entries configure local and remote Devices files for a hardwired connection between systems zeus and hera, where zeus is considered the local system and hera the remote system. The hardwired device on system zeus is tty1; on system hera, it is tty2.
The Devices file on system zeus contains the following entry in order to connect to the remote system, hera:
```
Direct tty1 - 1200 direct
hera tty1 - 1200 direct
```
The Devices file on system hera contains the following entry for communications with system zeus:
```
Direct tty2 - 1200 direct
zeus tty2 - 1200 direct
```
To configure a telephone connection, note the following information.
These files are set up to connect systems venus and merlin over a telephone line using modems. System venus is considered the local system, and system merlin is considered the remote system.

On both systems, the device tty1 is hooked to a hayes modem at 1200 baud. Both computers include partial phone numbers in their /etc/uucp/Systems files and dialing codes in their /etc/uucp/Dialcodes files.
The Devices file on system venus contains the following entry for the connection to system merlin:
```
ACU tty1 - 1200 hayes \T
```
The Devices file on system merlin contains the following entry for the connection to system venus:
```
ACU tty1 - 1200 hayes \T
```

Files

Item	Description
/etc/uucp directory	Contains all the configuration files for BNU, including the Devices file.
/etc/uucp/Dialcodes file	Contains dialing code abbreviations.
/etc/uucp/Dialers file	Specifies initial handshaking on a connection.
/etc/uucp/Systems file	Describes accessible remote systems.
/etc/uucp/Sysfiles file	Specifies possible alternative or augmentative files for /etc/uucp/Devices.