Dialers(4)Dialers(4)NAMEDialers - 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 pro‐
gram 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 config‐
ured 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 spec‐
ifies 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.
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 hand‐
shaking 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 con‐
nect 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. 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 char‐
acter in that set.
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Entry BAction
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=,-, 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.
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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 handshak‐
ing 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
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 connec‐
tions do not require any handshaking. Similarly, the last
entry, TCP, indicates that TCP/IP connections require no hand‐
shaking. 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 Handshak‐
ing field. Following is an explanation of how each entry
affects the action of the dialer. Translates the telephone num‐
ber. Any = (equal sign) represents wait for dial tone and any -
(dash) represents pause. Waits for nothing; continues with the
rest of the string. Delays, then sends AT (the Hayes Attention
prefix). Sends a carriage return (r) followed by a newline (c).
Waits for OK from the remote modem, signaling that the first
part of the string was executed. Pauses (p), then sends ATDT.
AT is again the Hayes Attention prefix, D represents a dialing
signal, and T represents a dial tone. Sends the telephone num‐
ber, which is specified in the /usr/lib/uucp/Systems file, with
dial-code translation from the /usr/lib/uucp/Dialcodes file.
Sends a carriage return and a newline following the number.
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 hand‐
shaking 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 hand‐
shaking. 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 tele‐
phone 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. 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
The Dialers file on system venus must contain the following entry for
its modem: hayes =,-, "" \dAT\r\c OK \pATDT\T\r\c CONNECT The
/usr/lib/uucp/Devices file on system merlin must contain the following
entry for the connection to system venus: ACU tty1 - 1200 hayes 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 difficul‐
ties 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: 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 cor‐
rect. Check the Dialers file and make sure the information is cor‐
rectly specified for the local modem. If possible, check the Dialers
file on the remote system also. 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
Contains all the configuration files for the uucp program, including
the Dialers file Contains information about available devices Contains
dial-code abbreviations Describes accessible remote systems
SEE ALSO
Daemons: uucico(8)
Commands: ct(1), cu(1), uutry(1)Dialers(4)