/etc/uucp/Devices File

The /etc/uucp/Devices file contains information for all the devices that can be used to establish a link to a remote computer. These devices include ACUs--which includes modern, high-speed modems--direct links, and network connections.

Each entry in the Devices file has the following format:

Here is an entry in /etc/uucp/Devices for a US Robotics V.32bis modem attached to port A and running at 38,400 bps.

ACUEC cua/a - 38400 usrv32bis-ec

Each field is described below.

Type Field

This field describes the type of link that the device establishes. It can contain one of the keywords described in the sections that follow:

Direct Keyword

The Direct keyword appears mainly in entries for cu connections. This keyword indicates that the link is a direct link to another computer or a port selector. Make a separate entry for each line that you want to reference through the -l option of cu.

ACU Keyword

The ACU keyword indicates that the link to a remote computer (whether through cu, UUCP, or PPP) is made through a modem. This modem can be connected either directly to your computer or indirectly through a port selector.

Port Selector

This is a variable that is replaced in the Type field by the name of a port selector. Port selectors are devices attached to a network that prompt for the name of a calling modem, then grant access. The file /etc/uucp/Dialers contains caller scripts only for the micom and develcon port selectors. You can add your own port selector entries to the Dialers file. (See "/etc/uucp/Dialers File" for more information.)

Sys-Name

This variable is replaced by the name of a machine in the Type field, indicating that the link is a direct link to this particular computer. This naming scheme is used to associate the line in this Devices entry to an entry in /etc/uucp/Systems for the computer Sys-Name.

Type Field and /etc/uucp/Systems File

Example 12-5 shows a comparison between the fields in /etc/uucp/Devices and fields in /etc/uucp/Systems. The titles of each column apply only to fields in the Devices file.

The keyword used in the Type field of the Devices file is matched against the third field of the Systems file entries, as indicated in Example 12-5. In the Devices file, the Type field has the entry ACUEC, indicating an automatic call unit, in this case a V.32bis modem. This value is matched against the third field in the Systems file, which also contains the entry ACUEC. (See "/etc/uucp/Systems File" for more information.)

Example 12-5 Type Field and /etc/uucp/Systems File Equivalent

File Name Type   Line  Line2 Class Dialer-Token-Pairs
 
Devices   ACUEC  cua/a -     38400 usrv32bis-ec
 
System    nubian Any   ACUEC 38400 9998888 "" \d\d\r\n\c-ogin-\r\n\c-ogin.......      
 

Line Field

This field contains the device name of the line (port) associated with the Devices entry. For instance, if the modem associated with a particular entry were attached to the /dev/cua/a device (serial port A), the name entered in this field would be cua/a. There is an optional modem control flag, M, that can be used in the Line field to indicate that the device should be opened without waiting for a carrier. For example:

cua/a,M

Line2 Field

This field is a placeholder. Always use a dash (-) here. 801 type dialers, which are not supported in the Solaris environment, use the Line2 field. Non-801 dialers do not normally use this configuration, but still require a hyphen in this field.

Class Field

The Class field contains the speed of the device, if the keyword ACU or Direct is used in the Type field. However, it can contain a letter and a speed (for example, C1200, D1200) to differentiate between classes of dialers (Centrex or Dimension PBX).

This is necessary because many larger offices can have more than one type of telephone network: one network might be dedicated to serving only internal office communications while another handles the external communications. In such a case, it becomes necessary to distinguish which line(s) should be used for internal communications and which should be used for external communications.

The keyword used in the Class field of the Devices file is matched against the Speed field of Systems file as shown in Example 12-6. Note that the titles of each column apply only to fields in the Devices file.

Example 12-6 Class Field and /etc/uucp/Systems Correspondence

File Name  Type   Line  Line2  Class  Dialer-Token-Pairs
 
Devices    ACU    cua/a -      D2400  hayes
 
System     gobi   Any   ACUEC  D2400  3251 ogin: nuucp ssword: taheya
 

Some devices can be used at any speed, so the keyword Any can be used in the Class field. If Any is used, the line matches any speed requested in the Speed field of the Systems file. If this field is Any and the Systems file Speed field is Any, the speed defaults to 2400 bps.

Dialer-Token-Pairs Field

The Dialer-Token-Pairs (DTP) field contains the name of a dialer and the token to pass it. The DTP field has this syntax:

dialer token [dialer token]

The dialer portion can be the name of a modem, a port monitor, or it can be direct or uudirect for a direct-link device. You can have any number of dialer-token pairs; if not present, it is taken from a related entry in the Systems file. The token portion can be supplied immediately following the dialer portion.

The last dialer token pair might not be present, depending on the associated dialer. In most cases, the last pair contains only a dialer portion. The token portion is retrieved from the Phone field of the associated Systems file entry.

A valid entry in the dialer portion can be defined in the Dialers file or can be one of several special dialer types. These special dialer types are compiled into the software and are therefore available without having entries in the Dialers file. Table 12-3 shows the special dialer types which include:

See "Protocol Definitions in the Devices File" for more information.

Structure of the Dialer-Token-Pairs Field

The DTP field can be structured four different ways, depending on the device associated with the entry:

• Directly connected modem

  If a modem is connected directly to a port on your computer, the DTP field of the associated Devices file entry has only one pair. This pair would normally be the name of the modem. This name is used to match the particular Devices file entry with an entry in the Dialers file. Therefore, the Dialer field must match the first field of a Dialers file entry as shown in Example 12-7. (The titles of each column apply only to fields in the Devices file.)

Example 12-7 Dialers Field and /etc/uucp/Dialers Correspondence

File Name Type  Line  Line2 Class Dialer-Token-Pairs
 
Devices   ACU   cua/b -     2400  hayes
 
Dialers   hayes =,-,  ""          \\dA\pTE1V1X1Q0S2=255S12=255\r\c 
                                  \EATDT\T\r\c CONNECT
 

Notice that only the dialer portion (hayes) is present in the DTP field of the Devices file entry. This means that the token to be passed on to the dialer (in this case the phone number) is taken from the Phone field of a Systems file entry. (\T is implied, as described in Example 12-9.)

• Direct link - For a direct link to a particular computer, the DTP field of the associated entry would contain the keyword direct. This is true for both types of direct-link entries, Direct and Sys-Name (refer to "Type Field").

• Computers on the same port selector - If a computer with which you want to communicate is on the same port selector switch as your computer, your computer must first access the switch. The switch then makes the connection to the other computer. This type of entry has only one pair. The dialer portion is used to match a Dialers file entry as shown in Example 12-8. (The titles of each column apply only to fields in the Devices file.)

Example 12-8 Dialers Field and /etc/uucp/Dialers Correspondence

File Name  Type     Line  Line2  Class  Dialer-Token-Pairs
 
Devices    develcon cua/a -      1200   develcon
 
Dialers    develcon ,""   ""            \pr\ps\c est:\007 \E\D\e \007
 

As shown, the token portion is left blank. This indicates that it is retrieved from the Systems file. The Systems file entry for this computer contains the token in the Phone field, which is normally reserved for the phone number of the computer. (Refer to "/etc/uucp/Systems File".) This type of DTP contains an escape character (\D), which ensures that the contents of the Phone field not interpreted as a valid entry in the Dialcodes file.

• Modems connected to port selector - If a high-speed modem is connected to a port selector, your computer must first access the port selector switch. The switch makes the connection to the modem. This type of entry requires two dialer-token-pairs. The dialer portion of each pair (fifth and seventh fields of entry) is used to match entries in the Dialers file, as shown in Example 12-7. (Notice that the titles of each column apply only to fields in the Devices file.)

Example 12-9 Dialers Field and /etc/uucp/Dialers Correspondence

File Name  Type     Line  Line2  Class     Dialer-Token-Pairs
 
Devices    ACU      cua/b -      1200      develcon    vent        ventel
 
Dialers    develcon ""    ""     \pr\ps\c  est:\007    \E\D\e      \007
 
Dialers    ventel   =&-%   t""   \r\p\r\c  $           <K\T%\r>\c  ONLINE!

In the first pair, develcon is the dialer and vent is the token that is passed to the Develcon switch to tell it which device (such as Ventel modem) to connect to your computer. This token is unique for each port selector since each switch can be set up differently. After the Ventel modem has been connected, the second pair is accessed, where Ventel is the dialer and the token is retrieved from the Systems file.

Two escape characters can appear in a DTP field:

• \T - Indicates that the Phone (token) field should be translated using the /etc/uucp/Dialcodes file. This escape character is normally placed in the /etc/uucp/Dialers file for each caller script associated with a modem (Hayes, US Robotics, and so on). Therefore, the translation does not take place until the caller script is accessed.

• \D - Indicates that the Phone (token) field should not be translated using the /etc/uucp/Dialcodes file. If no escape character is specified at the end of a Devices entry, the \D is assumed (default). A \D is also used in the /etc/uucp/Dialers file with entries associated with network switches (develcon and micom).

Protocol Definitions in the Devices File

You can define the protocol to use with each device in /etc/uucp/Devices. This is usually unnecessary because you can use the default or define the protocol with the particular system you are calling. (Refer to "/etc/uucp/Systems File".) If you do specify the protocol, you must use the form:

Type,Protocol [parameters]

For example, you can use TCP,te to specify the TCP/IP protocol.

Table 12-4 shows the available protocols for the Devices file:

Here is an example showing a protocol designation for a device entry:

TCP,te - - Any TCP - 

This example indicates that, for device TCP, try to use the t protocol. If the other end refuses, use the e protocol.

Neither e nor t is appropriate for use over modems. Even if the modem assures error-free transmission, data can still be dropped between the modem and the CPU.