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Dialers(4)
NAME
Dialers - Lists modems used for uucp remote communications links
SYNOPSIS
/usr/lib/uucp/Dialers
DESCRIPTION
The /usr/lib/uucp/Dialers file lists the modems used by the uucp program
and specifies the initial handshaking necessary to establish remote
communications links. Handshaking is a series of expect-send sequences that
specify the initial communications that occur on a link before it is ready
to send or receive data. Using the handshaking, the local and remote
systems confirm that they are compatible and configured to transfer data.
The Dialers file contains an entry for each autodialer that is included in
/usr/lib/uucp/Devices file. It also contains entries specifying no
handshaking for direct hardware links (the direct entry) and TCP/IP links
(the TCP entry). The first field of the Dialers file, which specifies the
dialer, is matched to the fifth field of the Devices file, the Dialer-Token
Pairs field, to determine handshaking when making a connection.
Note that only someone with superuser authority can edit the Dialers file,
which is owned by the uucp program login ID.
Fields in the Dialers File
Every modem is listed on a line by itself in the Dialers file. Each line
consists of three groups of information: the Dialer Name field, the Dial
Tone and Wait Characters field, and the Handshaking field.
Dialer Name Field
The first field in the Dialers file, the Dialer Name field, specifies
the type of autodialer (modem) used in the connection. It matches the
fifth field in the /usr/lib/uucp/Devices file, the Dialer-Token Pairs
field. When a particular device is used to make a connection, uucp
uses the Dialer-Token Pairs field in the Devices file to find the
handshaking entry in the Dialers file. If your system has direct
hardware connections to one or more remote systems, include an entry
with a Dialer Name of direct. Similarly, if your system uses TCP/IP to
connect to one or more other systems, include an entry with a Dialer
Name of TCP. These entries correspond to the word direct or the word
TCP in the Dialer-Token Pairs field of entries in the
/usr/lib/uucp/Devices file. Omit the Dial Tone and Wait Characters
field and the Handshaking field, since no handshaking is needed on
these connections.
Dial Tone and Wait Characters
The second field, the Dial Tone and Wait Characters field, consists of
two sets of two characters, for a total of four entries. These
characters comprise a translation string. In the actual telephone
number of the remote modem, the first character in each string is
mapped to the second character in that set.
___________________________________________________________
Entry BAction
___________________________________________________________
=,-,
Translates the telephone number. Any = (equal
sign) represents wait for dial tone and any -
(dash) represents pause.
""
Waits for nothing; continues with the rest of the
string. This field generally translates the = and -
characters into whatever the dialer uses for wait
for dial tone and pause. For direct and TCP
entries, omit this field.
___________________________________________________________
Handshaking Field
The handshaking, or dialer negotiations, is an expect-send sequence of
ASCII strings. It is given in the Handshaking field, which comprises
the remainder of the entry. This string is generally used to pass
telephone numbers to a modem, or to make a connection to another system
on the same data switch as the local system. The string tells the cu
or ct programs or the uucico daemon the sequence of characters to use
to dial out on a particular type of modem. If the connection succeeds,
the line in the Dialers file is interpreted to perform the dialer
negotiations.
The handshaking characters include entries such as \d to specify a
delay, \p for a pause, \r for a carriage return, and \c for a newline.
To determine the appropriate entries in the handshaking string, refer
to the documentation that accompanied the modems that you are including
in the Dialers file, and to the list of expect-send sequences given in
the /usr/lib/uucp/Systems file format. For direct and TCP entries, omit
this field.
EXAMPLES
Several types of Dialers file entries are shown below.
Setting Up Entries in the Dialers File
1. The following example lists several entries in a typical Dialers file:
hayes =,-, "" \dAT\r\c OK \pATDT\T\r\c CONNECT
penril =W-P "" \d > s\p9\c )-W\p\r\ds\p9\c-) y\E\TP > 9\c OK
ventel =&-% "" \r\p \r\p-\r\p-$ <K\D%%\r>\c ONLINE!
vadiac =K-K "" \005\p *-\005\p-* D\p BER? \E\D\e \r\c LINE
direct
TCP
Note that in the Dialers file, each entry must be entirely on one
line.
Note that the next to last entry in this example consists only of the
word direct. This entry indicates that hardwired connections do not
require any handshaking. Similarly, the last entry, TCP, indicates
that TCP/IP connections require no handshaking.
2. The following example interprets the first line in the preceding
Dialers file. This is a standard entry that may be included in your
Dialers file with modifications for use at your site.
hayes =,-, "" \dAT\r\c OK \pATDT\T\r\c CONNECT
The two sequences =,-, and "" comprise the Dial Tone and Wait
Characters field. The remaining strings comprise the Handshaking
field. Following is an explanation of how each entry affects the
action of the dialer.
=,-,
Translates the telephone number. Any = (equal sign) represents
wait for dial tone and any - (dash) represents pause.
"" Waits for nothing; continues with the rest of the string.
\dAT
Delays, then sends AT (the Hayes Attention prefix).
\r\c
Sends a carriage return (r) followed by a newline (c).
OK Waits for OK from the remote modem, signaling that the first part
of the string was executed.
\pATDT
Pauses (p), then sends ATDT. AT is again the Hayes Attention
prefix, D represents a dialing signal, and T represents a dial
tone.
\T Sends the telephone number, which is specified in the
/usr/lib/uucp/Systems file, with dial-code translation from the
/usr/lib/uucp/Dialcodes file.
\r\c
Sends a carriage return and a newline following the number.
CONNECT
Waits for CONNECT from the remote modem, signaling that the modems
are connected at the baud rate specified in the
/usr/lib/uucp/Devices file.
Note that if you need to modify this example for use at your site and
are unsure about the appropriate entries in the handshaking string,
refer to the documentation that accompanied the modems that you are
including in the Dialers file.
Setting Up the Direct Entry
If your uucp configuration includes hardwired connections, the Dialers file
must contain the direct entry. Enter:
direct
This entry indicates that hardwired connections do not require any
handshaking. It corresponds to the word direct in the Dialer-Token Pairs
field of the entries for hardwired devices in the /usr/lib/uucp/Devices
file.
Setting Up the TCP/IP Entry
If your uucp configuration includes TCP/IP connections, the Dialers file
must contain the TCP entry. Enter:
TCP
This entry indicates that TCP/IP connections do not require any
handshaking. It corresponds to the word TCP in the Dialer-Token Pairs
field of the entries for TCP/IP connections in the /usr/lib/uucp/Devices
file.
Setting Up Entries for Both Local and Remote Systems
The following examples illustrate the entries needed in the Dialers file to
correspond to entries in the /usr/lib/uucp/Devices file for both local and
remote systems so that the two systems can communicate using the uucp
program.
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 tty1 device
is hooked to a hayes modem at 1200 baud.
1. The /usr/lib/uucp/Devices file on system venus must contain the
following entry for the connection to remote system merlin:
ACU tty1 - 1200 hayes
2. The Dialers file on system venus must contain the following entry for
its modem:
hayes =,-, "" \dAT\r\c OK \pATDT\T\r\c CONNECT
3. The /usr/lib/uucp/Devices file on system merlin must contain the
following entry for the connection to system venus:
ACU tty1 - 1200 hayes
4. The Dialers file on system merlin must contain the following entry for
its modem:
hayes =,-, "" \dAT\r\c OK \pATDT\T\r\c CONNECT
Troubleshooting Connection Problems
When establishing a connection between a local and a remote system using a
telephone line and modem, the uucp program consults the Dialers file. (The
uucp program also checks the /usr/lib/uucp/Systems file to make sure it
contains a listing for the specified remote computer.) If users report a
faulty connection, use the uucico command to debug the connection problem.
For example, if users are experiencing difficulties connecting to remote
system venus, enter:
/usr/lib/uucp/uucico -r1 -svenus -x9
where -r1 specifies the server mode, -svenus is the name of the remote
system to which you are trying to connect, and -x9 is the debug level that
produces the most detailed debugging information.
Expect-send debugging output produced by the uucico command can come either
from information in the Dialers file or from information in the
/usr/lib/uucp/Systems file. If the relevant line in the Dialers file is not
set up correctly for the specified modem, the uucp program will probably
display the following error message:
DIALER SCRIPT FAILED
If the dialer script fails, verify the following:
1. Make sure that both the local and the remote modems are turned on,
that they are both set up correctly, and that the telephone number of
the remote modem is correct.
2. Check the Dialers file and make sure the information is correctly
specified for the local modem. If possible, check the Dialers file on
the remote system also.
3. Check the documentation that came with your modem to make sure you
have used the correct expect-send sequence characters in the Dialers
file.
FILES
/usr/lib/uucp/*
Contains all the configuration files for the uucp program, including
the Dialers file
usr/lib/uucp/Devices
Contains information about available devices
/usr/lib/uucp/Dialcodes
Contains dial-code abbreviations
/usr/lib/uucp/Systems
Describes accessible remote systems
SEE ALSO
Daemons: uucico(8)
Commands: ct(1), cu(1), uutry(1)
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Index for
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Alphabetical
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