faxing via efax falsely reports busy intermittently

[neil.t...@callcentrenorth.com]

I've built a fax server based around Linux. I'm using 2 Comtrol
RockertPort serial cards with 8 RS232 serial ports on each card and I've
created a bunch of scripts to automatically listen for faxes via 'efax'
and update our Intranet on the fly. This works absolutely fine.
The main problem I'm having is that when I send faxes it works
intermittently which has left me completely confused!!!

When I send a fax to a number, the modem (Askey Magic Express 56k/V.90
external voice/fax/data modem) dials correctly but hangs up
and reports the line as "BUSY" after a couple of rings. The length of
time that it rings varies from about 10 seconds to 50 seconds sometimes
but as long as the target fax machine answers in time, I get a
delivered fax.

On one particular line that I call, the modem is programmed to answer
after 4 rings but the modem always seems to report busy
before it can answer. One thing I have noted is that the faxes
generally go through the first time after I boot up the PC so it leads
me to believe
that the software is possibly not configured correctly.

I've tested it by calling standard phone lines with 'fax send' and it
still reports busy for landlines or mobiles. However, when I call my
mobile
manually by using ATDTxxxxxxx, it doesn't show a false busy so the
hardware appears to be OK.

I'm using efax 0.9a using its standard generic modem commands but these
can be changed.

I've looked at the commands in the manual but only one appears to state
how long the phone waits before a carrier but this reports
'NO ANSWER' instead of busy. Has anyone got any ideas about what is
causing this? Any ideas will be warmly appreciated!!!

[This is the output log from efax on a failed fax]
[I've marked some parts with a * to indicate my comments]

****log starts here
/usr/bin/efax: Tue Feb 29 12:19:18 2000 efax v 0.9a-990411 Copyright
1999 Ed Casas
efax: 19:18 compiled Feb 29 2000 09:59:09
efax: 19:18 TIFF version 4.2 file (little-endian)
efax: 19:18 TIFF directory at 8 with 18 tags, last image.
efax: 19:18 page 1 : /root/teams/00/000223163409.001 + 246 : 1728x1130 @
204x98 dpi TIFF/FAX
efax: 19:18 argv[0]=/usr/bin/efax
efax: 19:18 argv[1]=-s
efax: 19:18 argv[2]=-v
efax: 19:18 argv[3]=ewin
efax: 19:18 argv[4]=-v
efax: 19:18 argv[5]=chewmainrxtf
efax: 19:18 argv[6]=-d/dev/ttyR0
efax: 19:18 argv[7]=-x
efax: 19:18 argv[8]=/var/lock/LCK..ttyR0
efax: 19:18 argv[9]=-iZ
efax: 19:18 argv[10]=-i&FE&D2S7=120
efax: 19:18 argv[11]=-i&C0
efax: 19:18 argv[12]=-iM1L2
efax: 19:18 argv[13]=-c
efax: 19:18 argv[14]=1,3,0,0,0,0,0,0
efax: 19:18 argv[15]=-l
efax: 19:18 argv[16]=01429 405981
efax: 19:18 argv[17]=-kZ
efax: 19:18 argv[18]=-h
efax: 19:18 argv[19]=00/02/29 12:19 VR (CJG) (01429 405981) -->
01642890000 p. %d/%d
efax: 19:18 argv[20]=-t
efax: 19:18 argv[21]=T01642890000
efax: 19:18 argv[22]=/root/teams/00/000223163409.001
efax: 19:18 created text lock file /var/lock/LCK..ttyR0
efax: 19:18 opened /dev/ttyR0
efax: 19:18 command "Q0V1"
efax: 19:18 waiting 2.0 s
efax: 19:18 .817 [ATQ0V1<CR><CR><LF>]
efax: 19:18 .817 [OK<CR><LF>]
efax: 19:18 response "OK"
efax: 19:18 command "Z"
efax: 19:18 waiting 5.0 s
efax: 19:18 .927 [ATZ<CR><CR><LF>]
efax: 19:19 .047 [OK<CR><LF>]
efax: 19:19 response "OK"
efax: 19:19 command "&FE&D2S7=120"
efax: 19:19 waiting 5.0 s
efax: 19:19 .157 [AT&FE&D2S7=120<CR><CR><LF>]
efax: 19:19 .167 [OK<CR><LF>]
efax: 19:19 response "OK"
efax: 19:19 command "&C0"
efax: 19:19 waiting 5.0 s
efax: 19:19 .287 [<CR><LF>OK<CR><LF>]
efax: 19:19 response "OK"
efax: 19:19 command "M1L2"
efax: 19:19 waiting 5.0 s
efax: 19:19 .397 [<CR><LF>OK<CR><LF>]
efax: 19:19 response "OK"
efax: 19:19 command "E0"
efax: 19:19 waiting 5.0 s
efax: 19:19 .507 [<CR><LF>OK<CR><LF>]
efax: 19:19 response "OK"
efax: 19:19 command "I3"
efax: 19:19 waiting 5.0 s
efax: 19:19 .617 [<CR><LF>V2.210-V90_2M_DLS<CR><LF>]
efax: 19:19 .627 [<CR><LF>OK<CR><LF>]
efax: 19:19 response "OK"
efax: 19:19 command "+FCLASS=?"
efax: 19:19 waiting 5.0 s
efax: 19:19 .747 [<CR><LF>0,1,2,1.0<CR><LF>]
efax: 19:19 .757 [<CR><LF>OK<CR><LF>]
efax: 19:19 response "OK"
efax: 19:19 command "+FCLASS=2"
efax: 19:19 waiting 5.0 s
efax: 19:19 .867 [<CR><LF>OK<CR><LF>]
efax: 19:19 response "OK"
efax: 19:19 command "+FMFR?"
efax: 19:19 waiting 5.0 s
efax: 19:19 .977 [<CR><LF>ROCKWELL <CR><LF>]
efax: 19:19 .987 [<CR><LF>OK<CR><LF>]
efax: 19:19 response "OK"
efax: 19:20 command "+FMDL?"
efax: 19:20 waiting 5.0 s
efax: 19:20 .107 [<CR><LF>AC/K56<HT><HT> <CR><LF>]
efax: 19:20 .117 [<CR><LF>OK<CR><LF>]
efax: 19:20 response "OK"
efax: 19:20 using V2.210-V90_2M_DLS ROCKWELL AC/K56 in class 2 *this is
definitely the correct modem
efax: 19:20 command "+FCR=1"
efax: 19:20 waiting 5.0 s
efax: 19:20 .227 [<CR><LF>OK<CR><LF>]
efax: 19:20 response "OK"
efax: 19:20 command "+FDCC=1,3,0,0,0,0,0,0"
efax: 19:20 waiting 5.0 s
efax: 19:20 .247 [<CR><LF>OK<CR><LF>]
efax: 19:20 response "OK"
efax: 19:20 command "+FLID=" 01429 405981""
efax: 19:20 waiting 5.0 s
efax: 19:20 .267 [<CR><LF>OK<CR><LF>]
efax: 19:20 response "OK"
efax: 19:20 dialing T01642890000
efax: 19:20 command "DT01642890000"
efax: 19:20 waiting 120.0 s ** at this point the line was ringing out
ok - according to this line we are waiting 120s
efax: 19:38 .557 [<CR><LF>BUSY<CR><LF>] **the modem has sent the busy
signal just 18seconds later though!?!?!
efax: 19:38 response "BUSY"
efax: 19:38 Warning: number is busy
efax: 19:38 failed -> /root/teams/00/000223163409.001
efax: 19:38 command "Q0V1"
efax: 19:38 waiting 2.0 s
efax: 19:38 .677 [<CR><LF>OK<CR><LF>]
efax: 19:38 response "OK"
efax: 19:38 command "Z"
efax: 19:38 waiting 5.0 s
efax: 19:38 .907 [<CR><LF>OK<CR><LF>]
efax: 19:38 response "OK"
efax: 19:38 read HDB pid 2064 [ 2064<LF>] from /var/lock/LCK..ttyR0
(our pid)
efax: 19:38 removed lock file /var/lock/LCK..ttyR0
efax: 19:38 done, returning 1 (number busy or modem in use)
***log ends here

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Before you buy.

[neil.t...@gmail.com]

On Wednesday, March 1, 2000 at 8:00:00 AM UTC, neil.t...@callcentrenorth.com wrote:
> I've built a fax server based around Linux. I'm using 2 Comtrol
> RockertPort serial cards with 8 RS232 serial ports on each card and I've
> created a bunch of scripts to automatically listen for faxes via 'efax'
> and update our Intranet on the fly. This works absolutely fine.
> The main problem I'm having is that when I send faxes it works
> intermittently which has left me completely confused!!!
>
> When I send a fax to a number, the modem (Askey Magic Express 56k/V.90
> external voice/fax/data modem) dials correctly but hangs up
> and reports the line as "BUSY" after a couple of rings. The length of
> time that it rings varies from about 10 seconds to 50 seconds sometimes
> but as long as the target fax machine answers in time, I get a
> delivered fax.

Hi younger me from 16 years ago!

Those modems were a nightmare! It would have easily been better to have the ISDN lines go straight into an ISDN card because then you could just handle the calls digitally. And the issue you have there is that the signal is analogue. When in fax send mode the modem makes a strange regular tone but at the same time you are also hearing the dial tone. They both have different periods and as a result the tones phase in and out bringing the duration between hearing the outgoing modem beep and the dial tone closer together until - whoops - they are as spaced apart as an engaged tone and the modem hangs up. The outgoing dial tone is pre-recorded by the telecoms company and you are probably listening to the same tone as everyone else! So when you make you call there is no predictable position for the two tones to be in and you can't predict when they will collide to produce a false busy tone. So sometimes it hangs up in seconds, sometimes minutes.

Disable monitoring of busy tones with the command ATX0. Yes, you will end up waiting for 30 seconds for an answer even when busy but it'll work :-)

PS: people still use fax machines.

PPS: When you sell your first house for a huge profit, spend it on Apple shares rather than another house.