efax - send/receive faxes with Class 1, 2 or 2.0 fax modem
(Please read the fax man page first.)
SYNOPSIS
efax [ options ] [ -t num [ file... ] ]
OPTIONS
Where options are:
-a cmd use the command ATcmd when answering the phone.
The default is "A".
-c caps set the local modem capabilities. See the sec
tion on capabilities below for the format and
meaning of caps. For Class 1 the default is
1,n,0,2,0,0,0,0 where n is the highest speed sup
ported by the modem. For Class 2 the default is
determined by the modem.
-d dev use the fax modem connected to device dev. The
default is /dev/modem.
-f fnt use font file fnt for generating the header. The
default is a built-in 8x16 font. See the efix(1)
-f option for the font file format.
-g cmd if a CONNECT (or DATA) response indicates a data
call, the shell /bin/sh is exec(2)'ed with cmd as
its command. cmd is a printf(3) format that may
contain up to 6 %d escapes which are replaced by
the baud rate following the most recent CONNECT
message. cmd typically exec's getty(8).
-h hdr put string `hdr' at the top of each page. The
first %d in `hdr' is replaced by the page number
and the second, if any, is replaced by the number
of pages being sent.
-i str
-j str
-k str send the command ATstr to the modem to initialize
it. -i commands are sent before the modem is put
fax mode, and -k commands just before efax exits.
The only default is a hang-up (ATH) command that
is sent before exiting only if no other -k
options are given. Multiple options may be used.
-l id set the local identification string to id. id
should be the local telephone number in interna
tional format (for example "+1 800 555 1212").
This is passed to the remote fax machine. Some
fax machines may not accept characters other than
numbers, space, and '+'.
-o opt use option opt to accommodate a non-standard fax
modem protocol. See the MODEM REQUIREMENTS sec
tion below for more details. The options are:
0 Force use of Class 2.0 fax modem commands. The
modem must support Class 2.0.
2 Force use of Class 2 fax modem commands. The
modem must support Class 2.
1 Force use of Class 1 fax modem commands. The
modem must support Class 1. By default efax
queries the modem and uses the first of the three
above classes which is supported by the modem.
a use software adaptive answer method. If the
first attempt to answer the call does not result
in a data connection within 8 seconds the phone
is hung up temporarily and answered again in fax
mode (see "Accepting both fax and data calls"
below).
e ignore errors in modem initialization commands.
f use "virtual flow control". efax tries to esti
mate the number of bytes in the modem's transmit
buffer and pauses as necessary to avoid filling
it. The modem's buffer is assumed to hold at
least 96 bytes. This feature does not work prop
erly with Class 2 modems that add redundant
padding to scan lines. Use this option only if
you have problems configuring flow control.
(XON/XOFF) flow control. Many modems will stop
responding if this option is used. See the sec
tion `Resolving Problems' before using this
option.
l halve the time between testing lock files when
waiting for other programs to complete. By
default this is 8 seconds. For example -olll sets
the interval to 1 second.
n ignore requests for pages to be retransmitted.
Use this option if you don't care about the qual
ity of the received fax or if the receiving
machine is too fussy. Otherwise each page may be
retransmitted up to 3 times.
r do not reverse bit order during data reception
for Class 2 modems. Only Multitech modems
require this option. Not normally required since
efax detects these modems.
x send XON (DC1) instead of DC2 to start data
reception. Applies to a very few Class 2 modems
only.
z delay an additional 100 milliseconds before each
modem initialization or reset command. The ini
tial delay is 100 ms. For example, -ozzz produces
a 400 ms delay. Use with modems that get con
fused when commands arrive too quickly.
-q n ask for retransmission of pages received with
more than n errors. Default is 10.
-r pat each received fax page is stored in a separate
file. The file name is created using pat as a
strftime(3) format string. A page number of the
form .001, .002, ... is appended to the file
name. If pat is blank ("") or no -r option is
given a default string of "%m%d%H%M%S" is used.
-s remove lock file(s) after initializing the modem.
This allows outgoing calls to proceed when efax
modem activity it will attempt to re-lock the
device. If the modem has been locked by the
other program efax will exit and return 1
(``busy''). Normally a new efax process is then
started by init(8). The new efax process will
then check periodically until the lock file dis
appears and then re-initialize the modem.
-t num [file...]
dial telephone number num and send the fax image
files file.... If used, this must be the last
argument on the command line. The telephone num
ber num is a string that may contain any dial
modifiers that the modem supports such as a T
prefix for tone dialing or commas for delays. If
no file names are given the remote fax machine
will be polled. If no -t argument is given efax
will answer the phone and attempt to receive a
fax.
-v strng select types of messages to be printed. Each
lower-case letter in strng enables one type of
message:
e - errors
w - warnings
i - session progress information
n - capability negotiation information
c - modem (AT) commands and responses
h - HDLC frame data (Class 1 only)
m - modem output
a - program arguments
r - reception error details
t - transmission details
f - image file details
x - lock file processing
Up to two -v options may be used. The first is
for messages printed to the standard error and
the second is for messages to the standard out
put. The default is "ewin" to the standard error
only.
-w wait for an OK or CONNECT prompt instead of issu
ing an answer (ATA) command to receive a fax.
Use this option when the modem is set to auto-
answer (using S0=n) or if another program has
already answered the call.
device before opening it. If the device is
locked, efax checks every 15 seconds until it is
free. Up to 16 -x options may be used if there
are several names for the same device. A `#'
prefix on the file name creates an binary rather
than text (HDB-style) lock file. This is the
reverse of what was used by previous efax ver
sions.
FAX FILE FORMATS
efax can read the same types of files as efix(1) including
text, T.4 (Group 3), PBM, single- and multi-page TIFF (G3
and uncompressed). efax automatically determines the type
of file from its contents. TIFF files are recommended as
they contain information about the image size and resolu
tion.
Each page to be sent should be converted to a separate
TIFF format file with Group 3 (G3) compression. Received
files are also stored in this format. The EXAMPLES sec
tion below shows how efix and other programs can be used
to create, view and print these files.
OPERATING SYSTEM REQUIREMENTS
The operating system must provide short response times to
avoid protocol timeouts. For Class 2 and 2.0 modems the
delay should not exceed 1 or 2 seconds.
When using Class 1 modems the program must respond to cer
tain events within 55 milliseconds. Longer delays may
cause the fax protocol to fail in certain places (between
DCS and TCF or between RTC and MPS). Class 1 modems
should therefore not be used on systems that cannot guar
antee that the program will respond to incoming data in
less than 55 milliseconds. In particular, some intelli
gent serial cards and terminal servers may introduce
enough delay to cause problems with Class 1 operation.
The operating system must also provide sufficient low-
level buffering to allow uninterrupted transfer of data
between the modem and a disk file at the selected baud
rate, typically 9600 bps. Since the fax protocol does not
provide end-to-end flow control the effectiveness of flow
control while receiving is limited by the size of the
modem's buffer. This can be less than 100 bytes. Efax
does not use flow control during reception.
MODEM REQUIREMENTS
The "Group" is the protocol used to send faxes between fax
machines. Efax supports the Group 3 protocol used over
The "Class" is the protocol used by computers to control
fax modems. Efax supports Class 1, 2 and 2.0 fax modems.
Most fax modems use XON/XOFF flow control when in fax
mode. This type of flow control adds very little overhead
for fax use. Many modems have unreliable hardware
(RTS/CTS) flow control in fax mode. By default efax
enables only XON/XOFF flow control and the -oh option must
be used to add hardware flow control.
While some modems have serial buffers of about 1k bytes,
many inexpensive modems have buffers of about one hundred
bytes and are thus more likely to suffer overruns when
sending faxes.
A few older modems may need a delay between commands of
more than the default value used by efax (100 millisec
onds). If the delay is too short, commands may not echo
properly, may time out, or may give inconsistent
responses. Use one or more -oz options to increase the
delay between modem initialization commands and use the E0
modem initialization command to disable echoing of modem
commands.
By default efax sends DC2 to start the data flow from the
modem when receiving faxes from Class 2 modems. A few
older modems require XON instead. Use of DC2 would cause
the modem to give an error message and/or the program to
time out. The -ox option should be used in this case.
A few older Class 2 modems (e.g. some Intel models) don't
send DC2 or XON to start the data flow to the modem when
sending faxes. After waiting 2 seconds efax will print a
warning and start sending anyways.
A very few Class 2 modems do not reverse the bit order
(MSB to LSB) by default on receive. This might cause
errors when trying to display or print the received files.
The -or option can be used in this case.
Some inexpensive "9600 bps" fax modems only transmit at
9600 bps and reception is limited to 4800 bps.
The following Class 1 modems have been reported to work
with efax: AT&T DataPort, Cardinal Digital Fax Modem
(14400), Digicom Scout+, Motorola Lifestyle 28.8, Motorola
Power 28.8, QuickComm Spirit II, Smartlink 9614AV-Modem,
Supra Faxmodem 144LC, USR Courier V.32bis Terbo, USR
Sportster (V.32 and V.34), Zoom AFC 2.400, Zoom VFX14.4V.
The following Class 2 modems have been reported to work
with efax: 14k4 Amigo Communion fax/modem, Adtech Micro
DataPort, ATT/Paradyne, AT&T Paradyne PCMCIA, Boca modem,
BOCA M1440E, Crosslink 9614FH faxmodem, FuryCard DNE 5005,
GVC 14.4k internal, Intel 14.4 fax modem, Megahertz 14.4,
, Microcom DeskPorte FAST ES 28.8, Motorola UDS FasTalk
II, MultiTech 1432MU, Practical Peripherals PM14400FXMT,
Supra V32bis, Telebit Worldblazer, TKR DM-24VF+, Twincom
144/DFi, ViVa 14.4/Fax modem, Vobis Fax-Modem (BZT-
approved), Zoom VFX14.4V, ZyXEL U-1496E[+], ZyXEL Elite
2864I.
MODEM INITIALIZATION OPTIONS
The required modem initialization commands are generated
by efax. Additional commands may be supplied as command-
line arguments. The modem must be set up to issue ver
bose(text) result codes. The following command does this
and is sent by efax before trying to initialize the modem.
Q0V1 respond to commands with verbose result codes
The following commands may be useful for special purposes:
X3 don't wait for dial tone before dialing. This
may be used to send a fax when the call has
already been dialed manually. In this case use
an empty string ("") as the first argument to the
-t command. Use X4 (usual default) to enable all
result codes.
M2 leave the monitor speaker turned on for the dura
tion of the call (use M0 to leave it off).
L0 turn monitor speaker volume to minimum (use L3
for maximum).
E0 disable echoing of modem commands. See the
Resolving Problems section below.
&D2 returns the modem to command mode when DTR is
dropped. The program drops DTR at the start and
end of the call if it can't get a response to a
modem command. You can use &D3 to reset the
modem when DTR is dropped.
S7=120 wait up to two minutes (120 seconds) for carrier.
takes a long time to start the handshaking opera
tion (e.g. a combined fax/answering machine with
a long announcement).
CAPABILITIES
The capabilities of the local hardware and software can be
set using a string of 8 digits separated by commas:
vr,br,wd,ln,df,ec,bf,st
where:
vr (vertical resolution) =
0 for 98 lines per inch
1 for 196 lpi
br (bit rate) =
0 for 2400 bps
1 for 4800
2 for 7200
3 for 9600
4 for 12000 (V.17)
5 for 14400 (V.17)
wd (width) =
0 for 8.5" (21.5 cm) page width
1 for 10" (25.5 cm)
2 for 12" (30.3 cm)
ln (length) =
0 for 11" (A4: 29.7 cm) page length
1 for 14" (B4: 36.4 cm)
2 for unlimited page length
df (data format) =
0 for 1-D coding
1 for 2-D coding (not supported)
ec (error correction) =
0 for no error correction
bf (binary file) =
0 for no binary file transfer
0 for zero delay per line
1 for 5 ms per line
3 for 10 ms per line
5 for 20 ms per line
7 for 40 ms per line
When receiving a fax the vr, wd, and ln fields of the
capability string should be set to the maximum values that
your display software supports. The default is 196 lpi,
standard (8.5"/21.5cm) width and unlimited length.
When sending a fax efax will determine vr and ln from the
image file and set wd to the default.
If the receiving fax machine does not support high resolu
tion (vr=1) mode, efax will reduce the resolution by com
bining pairs of scan lines. If the receiving fax machine
does not support the image's width then efax will truncate
or pad as required. Most fax machines can receive ln up to
2. Few machines support values of wd other than 0.
HEADERS
efax adds blank scan lines at the top of each image when
it is sent. This allows room for the page header but
increases the length of the image (by default about 0.1"
or 2.5mm of blank space is added).
The header placed in this area typically includes the date
and time, identifies the, and shows the page number and
total pages. Headers cannot be disabled but the header
string can be set to a blank line.
The default font for generating the headers is the built-
in 8x16 pixel font scaled to 12x24 pixels (about 9 point
size).
Note that both efax and efix have -f options to specify
the font. efIx uses the font to generate text when doing
text-to-fax conversions (during "fax make") while efAx
uses the font to generate the header (during "fax send").
SESSION LOG
A session log is written to the standard error stream.
This log gives status and error messages from the program
as selected by the -v option. A time stamp showing the
full time or just minutes and seconds is printed before
each message. Times printed along with modem responses
also show milliseconds.
The program returns an error code as follows:
0 The fax was successfully sent or received.
1 The dialed number was busy or the modem device
was in use. Try again later.
2 Something failed (e.g. file not found or disk
full). Don't retry. Check the session log for
more details.
3 Modem protocol error. The program did not
receive the expected response from the modem.
The modem may not have been properly initialized,
the correct -o options were not used, or a bug
report may be in order. Check the session log
for more details.
4 The modem is not responding. Operator attention
is required. Check that the modem is turned on
and connected to the correct port.
5 The program was terminated by a signal.
EXAMPLES
Creating fax (G3) files
The efix program can be used to convert text files to
TIFF-G3 format. For example, the following command will
convert the text file letter to the files letter.001, let
ter.002, etc,:
efix -nletter.%03d letter
Ghostscript's tiffg3 driver can generate fax files in
TIFF-G3 format from postscript files. For example, the
command:
gs -q -sDEVICE=tiffg3 -dNOPAUSE \
-sOutputFile=letter.%03d letter.ps </dev/null
will convert the Postscript file letter.ps into high-
ter.002, ...
The images should have margins of at least 1/2 inch (1 cm)
since the fax standard only requires that fax machines
print a central portion of the image 196.6mm (7.7 inches)
wide by 281.5mm (11.1 inches) high.
The efix program can also insert bitmaps in images to cre
ate letterhead, signatures, etc.
Printing fax files
You can use the efix program to print faxes on Postscript
or HP-PCL (LaserJet) printers. For example, to print the
received fax file reply.001 on a Postscript printer use
the command:
efix -ops reply.001 | lpr
Sending fax files
The following command will dial the number 222-2222 using
tone dialing and send a two-page fax from the TIFF-G3
files letter.001 and letter.002 using the fax modem con
nected to device /dev/cua1.
efax -d /dev/cua1 \
-t T222-2222 letter.001 letter.002
Manual answer
You can use efax to answer the phone immediately and start
fax reception. Use this mode if you need to answer calls
manually to see if they are fax or voice.
For example, the following command will make the fax modem
on device /dev/ttyS1 answer the phone and attempt to
receive a fax. The received fax will be stored in the
files reply.001, reply.002, and so on. The modem will
identify itself as "555 1212" and receive faxes at high or
low resolution (vr=1), at up to 14.4 kbps (br=5).
efax -d /dev/ttyS1 -l "555 1212" \
-c 1,5 -r reply
Automatic answer
available from the modem (indicating an incoming call)
before starting fax reception. Use the -w option and a
-iS0=n option to answer the phone after n rings. The
example below will make the modem answer incoming calls in
fax mode on the fourth ring and save the received faxes
using files names corresponding to the reception date and
time.
efax -d /dev/ttyb -w -iS0=4 2>&1 >> fax.log
Sharing the modem with outgoing calls
The modem device can be shared by programs that use the
UUCP device locking protocol. This includes pppd, chat,
minicom, kermit, uucico, efax, cu, and many others others.
However, locking will only work if all programs use the
same lock file.
efax will lock the modem device before opening it if one
or more UUCP lock file names are given with -x options.
Most programs place their lock files in the
/usr/spool/uucp or /var/lock directories and use the name
LCK..dev where dev is the name of the device file in the
/dev directory that is to be locked.
If the -s (share) option is used, the lock file is removed
while waiting for incoming calls so other programs can use
the same device.
If efax detects another program using the modem while it
is waiting to receive a fax, efax exits with a termination
code of 1. A subsequent efax process using this device
will wait until the other program is finished before re-
initializing the modem and starting to wait for incoming
calls again.
Programs that try to lock the modem device by using device
locking facilities other than UUCP lock files not be able
to use this arbitration mechanism because the device will
still be open to the efax process. In this case you will
need to kill the efax process (e.g. "fax stop") before
starting the other program.
When efax is waiting for a fax it leaves the modem ready
to receive in fax mode but removes the lock file. When a
slip or PPP program takes over the modem port by setting
up its own lock file efax cannot send any more commands to
the modem -- not even to reset it. Therefore the other
program has to set the modem back to data mode when it
starts up. To do this add a modem reset command (send ATZ
expect OK) to the beginning of your slip or PPP chat
Accepting both fax and data calls
Many modems have an adaptive data/fax answer mode that can
be enabled using the -j+FAE=1 (for Class 1) or -jFAA=1
(for Class 2[.0]) initialization string. The type of call
(data or fax) can then be deduced from the modem's
responses.
Some modems have limited adaptive answer features (e.g.
only working properly at certain baud rates or only in
Class 2) or none at all. In this case use the initializa
tion string -i+FCLASS=0 to answer in data mode first and
the -oa option to then hang up and try again in fax mode
if the first answer attempt was not successful. This
method only works if your telephone system waits a few
seconds after you hang up before disconnecting incoming
calls.
If the -g option is used then the option's argument will
be run as a shell command when an incoming data call is
detected. Typically this command will exec getty(8).
This program should expect to find the modem already off-
hook and a lock file present so it should not try to hang
up the line or create a lock file. Note that the modem
should be set up to report the DCE-DTE (modem-computer,
e.g. CONNECT 38400) speed, not the DCE-DCE (modem-modem,
e.g. CONNECT 14400) speed. For many modems the initial
ization option -iW0 will set this.
The following command will make efax answer incoming calls
on /dev/cua1 on the second ring. This device will be
locked using two different lock files but these lock files
will be removed while waiting for incoming calls (-s). If
a data call is detected, the getty program will be run to
initialize the terminal driver and start a login(1) pro
cess. Received fax files will be stored using names like
Dec02-12.32.33.001, in the /usr/spool/fax/incoming direc
tory and the log file will be appended to
/usr/spool/fax/faxlog.cua1.
efax -d /dev/cua1 -j '+FAA=1' \
-x /usr/spool/uucp/LCK..cua1 \
-x /usr/spool/uucp/LCK..ttyS1 \
-g "exec /sbin/getty -h /dev/cua1 %d" \
-iS0=2 -w -s \
-r "/usr/spool/fax/incoming/%b%d-%H.%I.%S" \
>> /usr/spool/fax/faxlog.cua1 2>&1
Note that adaptive answer of either type will not work for
all callers. For some data calls the duration of the
shaking to complete. In other cases this duration may be
so long that incoming fax calls will time out before efax
switches to fax mode. In addition, some calling fax
modems mistake data-mode answering tones for fax signaling
tones and initiate fax negotiation too soon. If you use
software adaptive answer you can reduce the value of the
initial data-mode answer (set by TO_DATAF in efax.c) to
get more reliable fax handshaking or increase it for more
reliable data handshaking. However, if you need to pro
vide reliable fax and data service to all callers you
should use separate phone numbers for the two types of
calls.
When a call is answered the modem goes on-line with the
computer-to-modem baud rate fixed at the speed used for
the most recent AT command. When efax is waiting for a
fax or data call it sets the interface speed to 19200 bps
since this is the speed required for fax operation. This
prevents full use of 28.8kbps modem capabilities.
USING INIT TO RUN EFAX
efax can answer all incoming calls if you place an entry
for efax in /etc/inittab (for SysV-like systems) or
/etc/ttytab (for BSD-like systems). The init(8) process
will run a new copy of efax when the system boots up and
whenever the previous efax process terminates. The init
tab or ttytab entry should invoke efax by running the fax
script with an answer argument.
For example, placing the following line in /etc/inittab
(and running "kill -1 1") will make init run the fax
script with the argument answer every time previous pro
cess terminates and init is in runlevel 4 or 5.
s1:45:respawn:/bin/sh /usr/bin/fax answer
For BSD-like systems (e.g. SunOS), a line such as the fol
lowing in /etc/ttytab will have the same effect:
ttya "/usr/local/bin/fax answer" unknown on
You should protect the fax script and configuration files
against tampering since init will execute them as a privi
leged (root) process. If you will be allowing data calls
via getty and login you should ensure that your system is
reasonably secure (e.g. that all user id's have secure
passwords).
login prompt then there is probably a baud rate mismatch
between the modem and the computer. First, check the efax
log file to make sure the modem's CONNECT response
reported the serial port speed (e.g. 19200), not the
modem-modem speed (e.g. 14400). Next, check the getty
options and/or configuration files (e.g. /etc/gettydefs)
for that particular baud rate. Then run getty manually
with the same arguments and verify the port settings using
``stty </dev/XXX''. Note that you'll probably want to
enable hardware flow control for data connections (-h for
agetty, CRTSCTS for getty_ps).
A few programs won't work properly when efax is set up to
answer calls because they don't create lock files. You
can put the shell script ``wrapper'' below around such
programs to make them work properly. Change BIN and LOCKF
to suit.
#!/bin/sh
BIN=/bin/badprogram
LOCKF=/var/spool/uucp/LCK..cua1
if [ -f $LOCKF ]
then
echo lock file $LOCKF exists
exit 1
else
printf "%10d0 $$ >$LOCKF
$BIN $*
rm $LOCKF
fi
DELIVERING RECEIVED FAXES BY E-MAIL
The "fax answer" script described above can be configured
to e-mail the fax files received by the previous fax
answer process to a "fax manager" who can then forward the
fax to the correct recipient. The received fax files are
send as MIME attachments, one file per page, using the
``base64'' text encoding and the ``image/tiff'' file for
mat.
To view the fax images directly from your e-mail reader
you will have to configure it with an application that can
display files of type image/tiff. Typically this is spec
ified in a ``mailcap'' file. For example, placing the
following line in /etc/mailcap will cause the fax file
attachments to be displayed using the ``fax view'' com
mand.
image/tiff; fax view %s
You can configure a "fax" printer into the lpr print
spooler that will fax a document out using efax instead of
printing it. This allows a network server running efax to
send faxes on behalf of other machines, including non-Unix
clients. In the following steps use the directories spec
ified in the fax script if they are different than
/usr/bin and /var/spool/fax (FAXDIR). To set up a fax
printer do the following as root:
(1) Create a link to the fax script called ``faxlpr'' so
the fax script can determine when it is being invoked from
the print spooler:
ln /usr/bin/fax /usr/bin/faxlpr
(2) Edit /etc/printcap and add an entry such as:
fax:lp=/dev/null:sd=/var/spool/fax:if=/usr/bin/faxlpr:
to define a printer called "fax". Print files will be
spooled to the /var/spool/fax (sd=) directory and then
piped to the /usr/bin/faxlpr filter (if=).
(3) Create and/or set the permissions to allow anyone to
read and write in the fax spool directory. For example:
mkdir /var/spool/fax
chmod 777 /var/spool/fax
(4) Create a printer daemon lock file that is readable by
anyone:
touch /var/spool/fax/lock
chmod 644 /var/spool/fax/lock
You should now be able to send a fax using the lpr inter
face by using a command such as:
lpr -P fax -J "555 1212" file.ps
where the -J option is used to specify the phone number or
alias to be dialed.
Note that if more than one file is given on the command
send". TIFF-G3, Postscript or PBM files must therefore be
sent one file at a time although TIFF and Postscript files
may contain multiple pages. Only multiple text files can
be sent in one command. Page breaks in text files can be
marked with form-feed characters. Files will be converted
and sent at the default (high) resolution.
You can use lpq(1) to check the fax queue, lprm(1) to
remove fax jobs and lpc(8) to control the spooler. In
each case use the -Pfax option to specify the fax
``printer.'' A log file will be mailed to the user when
the fax is sent.
You should also be able to send a fax from any networked
computer that has lpr-compatible remote printing software
and that allows you to set the job name (-J option) to an
arbitrary string. Such software is available for most
computers.
See the lpd(8) and printcap(5) man pages for information
on the print spooler and for restricting access by host
name (/etc/host.lpd) or by user group (the `rg' printcap
entry).
RESOLVING PROBLEMS
Double check the configuration setup in the first part of
the fax script, particularly the modem device name and the
lock file names.
If efax hangs when trying to open the modem device (typi
cally /dev/ttyX), the device is either already in use by
another process (e.g. pppd) or it requires the carrier
detect line to be true before it can be opened. Many sys
tems define an alternate device name for the same physical
device (typically cuaX) that can be opened even if carrier
is not present or other programs are already using it.
If responses to modem initialization commands are being
lost or generated at random, another processes (e.g. getty
or an efax auto-answer process) may be trying to use the
modem at the same time. Try running efax while this other
program is running. If efax does not report "/dev/ttyX
locked or busy. waiting." then the lock files names are
not specified correctly.
Attempt to send a fax. Check that the modem starts making
the calling signal (CNG, a 0.5 second beep every 3 sec
onds) as soon as it's finished dialing. This shows the
modem is in fax mode. You may need to set the SPKR vari
able to -iM2L3 to monitor the phone line to do this.
Listen for the answering fax machine and check that it
"warbling" sounds (DIS frames) every 3 seconds. If you
hear a continuous sound (tones or noise) instead, then
you've connected to a data modem instead.
Your modem should send back its own warble (DCS frame) in
response to DIS immediately followed by 1.5 seconds of
noise (a channel check). If everything is OK, the receiv
ing end will send another warble (CFR frame) and your
modem will start to send data. If you have an external
modem, check its LEDs. If flow control is working prop
erly the modem's send data (SD) LED will turn off periodi
cally while the fax data is sent.
Check the message showing the line count and the average
bit rate when the page transmission is done. Low line
counts (under 1000 for a letter size image) or the warning
"fax output buffer overflow" while sending indicate that
the image data format is incorrect. Check the file being
sent using the "fax view" command.
If you get the error message ``flow control did not work''
then flow control was not active. This usually results in
a garbled transmission and the receiving machine may
reject the page, abort the call, print a distorted or
blank image and/or hang up.
The warning "characters received while sending" or an
<XOFF> character appearing after the transmission means
that the operating system ignored the modem's XOFF flow
control character. Ensure that you are not running other
programs such as getty or pppd at the same time as efax
since they will turn off xon/xoff flow control.
If you cannot get flow control to work properly then
enable ``virtual flow control'' with the -of option or
hardware flow control with the -oh option.
Check that the remote machine confirms reception with a
+FPTS:1 response (Class 2) or an MCF frame (Class 1).
For Class 2 modems, the error message "abnormal call ter
mination (code nn)" indicates that the modem detected an
error and hung up.
Many companies advertise services that will fax back
information on their products. These can be useful for
testing fax reception.
The message "run length buffer overflow" when receiving
indicates an error with the image data format. You may
need to use the -or option with certain Class 2 modems.
If efax displays the message "can't happen (<details>)"
Finally, don't play "option bingo," if you can't resolve
the problem send a verbose log of the failed session (the
output from fax -v ...) to the address below.
WEB PAGE
A Web Page with pointers to the latest version, known bugs
and patches is available at:
http://casas.ee.ubc.ca/efax/
RELATED SOFTWARE
For Linux Systems
Independent packages provide more user-friendly interfaces
to efax (xfax, tefax) and provide an e-mail-to-fax (Qfax)
gateway using efax. All are available by anonymous FTP
from metalab.unc.edu in /pub/Linux/apps/serialcomm/fax/.
For Amiga Systems
A port of an early version of efax for the Amiga is avail
able as a component of a shareware voice mail package,
AVM, distributed by Al Villarica (rvillari@cat.syr.edu).
Other Ports
efax is relatively easy to port. All system-dependent
code is in efaxos.c. An early version of efax was ported
to VMS. Version 0.8a was ported to Win32 by Luigi Capri
otti. Contact the author if you would like to integrate
the Win32 code into the current version.
AUTHOR
Efax was written by Ed Casas. Please send comments or bug
reports to edc@cce.com.
BUG REPORTS
Bug reports should include the operating system, the type
of the modem and a copy of a verbose session log that
demonstrates the problem. It's usually impossible to help
without a verbose log. Please do not send fax image
files.
COPYRIGHT
efax is copyright 1993 -- 1999 Ed Casas. It may be used,
copied and modified under the terms of the GNU Public
DISCLAIMER
Although efax has been tested it may have errors that will
prevent it from working correctly on your system. Some of
these errors may cause serious problems including loss of
data and interruptions to telephone service.
REFERENCES
CCITT Recommendation T.30, "Procedures for Document Fac
simile Transmission in the General Switched Telephone Net
work". 1988
CCITT Recommendation T.4, "Standardization of Group 3 Fac
simile Apparatus for Document Transmission". 1988.
For documentation on Class 1 and Class 2 fax commands as
implemented by Connexant (formerly Rockwell) modems see
http://www.conexant.com/techinfo.
For the TIFF specification see http://part
ners.adobe.com/supportservice/devrela
tions/PDFS/TN/TIFF6.pdf or RFC 2301 (ftp://ftp.isi.edu/in-
notes/rfc2301.txt).
For information on Ghostscript see
http://www.cs.wisc.edu/~ghost/.
The pbm utilities can be obtained by ftp from
wuarchive.wustl.edu in /graphics/graphics/pack
ages/NetPBM/netpbm-1mar1994.tar.gz.
PCX and many other file formats are described in: Gunter
Born, The File Formats Handbook, International Thomson
Computer Press, 1995.
The "Fax Modem Source Book" by Andrew Margolis, published
by John Wiley & Sons in 1994 (ISBN 0471950726), is a book
on writing fax applications which includes source code.
Dennis Bodson et. al., "FAX: Digital Facsimile Technology
and Applications", Second Edition. Artech House, Boston.
1992.
SEE ALSO
fax(1), efix(1), gs(1), init(8), inittab(5), ttytab(5),
printcap(5), lpd(8), printf(3), strftime(3).
BUGS
Can't read TIFF files with more than 1 strip
certain data received from the modem within 55 millisec
onds.
May fail if multitasking delays cause the received data to
overflow the computer's serial device buffer or if an
under-run of transmit data exceeds 5 seconds.
Polling does not work.
Does not support 2-D coding, ECM, or BFT.
Man(1) output converted with
man2html