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- David Segall
December 4, 2005, 4:01 pm

I am writing a program that outputs DTMF tones from my computer
speakers to dial telephone numbers in my address book. I decided to
add a button to do automatic call back if the number is engaged. The
instructions in the phone book which are also here -
<http://telstra-fixed.custhelp.com/cgi-bin/telstra_fixed.cfg/php/enduser/std_adp.php?p_faqid11%54&p_created11%11370527&p_sid=v_z-edWh&p_lva=&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9MyZwX3Byb2RzPTAmcF9jYXRzPSZwX3B2PSZwX2N2PSZwX3BhZ2U9MSZwX3NlYXJjaF90ZXh0PXJlY2FsbA **&p_li=&p_topview=1>
say to press "Recall" then *37#. Can I send tones to emulate "Recall"
or is it some other change of state on the phone line? If the latter,
what is it?

Re: How do you say "Recall" to a telephone?

<http://telstra-fixed.custhelp.com/cgi-bin/telstra_fixed.cfg/php/enduser/std_adp.php?p_faqid11%54&p_created11%11370527&p_sid=v_z-edWh&p_lva=&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9MyZwX3Byb2RzPTAmcF9jYXRzPSZwX3B2PSZwX2N2PSZwX3BhZ2U9MSZwX3NlYXJjaF90ZXh0PXJlY2FsbA **&p_li=&p_topview=1>

Wouldn't it be easier just to send the number again?
Cheers.
Ken

Re: How do you say "Recall" to a telephone?

<http://telstra-fixed.custhelp.com/cgi-bin/telstra_fixed.cfg/php/enduser/std_adp.php?p_faqid11%54&p_created11%11370527&p_sid=v_z-edWh&p_lva=&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9MyZwX3Byb2RzPTAmcF9jYXRzPSZwX3B2PSZwX2N2PSZwX3BhZ2U9MSZwX3NlYXJjaF90ZXh0PXJlY2FsbA **&p_li=&p_topview=1>

That would be fine but it does not seem to work. I have tried sending
the number followed by *37# in response to the engaged tone. I have
also tried some variants involving one second pauses but all I get is
the engaged tone. Is there some way of sending the number that you
believe will work?

Re: How do you say "Recall" to a telephone?

If you are getting busy tone, then you *must* hang up. Dialling anything
else without hanging first is just pointless. Try it manually. The
Recall code (*37#) is only a command that indicates that something else
is to follow, it certainly is not the equivalent of hanging up & letting
the line reset.
Kevin Martin

Re: How do you say "Recall" to a telephone?

I think you are right but I was responding to a post that proposed
sending the number again. "Hanging up first" does not solve my problem
because sending the original number after hanging up, not
surprisingly, results in the engaged signal again.

I don't understand this bit. *37# does not expect anything else to
follow. Trying it manually indicates that if it is preceded by Recall
(Flash) it results in the Call Back behaviour I am seeking.


Re: How do you say "Recall" to a telephone?
["Followup-To:" header set to aus.electronics.]

so when the busy tone is detected you need to flash the hook (send the
recall pulse) and then send the tones, to flash the hook all other
devices on that line must be on hook. or the CO will only see a click.
how are you controlling the phone line?
--
Bye.
Jasen
Bye.
Jasen

Re: How do you say "Recall" to a telephone?

"Controlling" is a bit of an overstatement. Franc Zabkar remembered
the modems of our youth and recalled the technical term. So I will say
that I am using an acoustic coupler. Here's my original post-

<http://telstra-fixed.custhelp.com/cgi-bin/telstra_fixed.cfg/php/enduser/std_adp.php?p_faqid11%54&p_created11%11370527&p_sid=v_z-edWh&p_lva=&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9MyZwX3Byb2RzPTAmcF9jYXRzPSZwX3B2PSZwX2N2PSZwX3BhZ2U9MSZwX3NlYXJjaF90ZXh0PXJlY2FsbA **&p_li=&p_topview=1>

Thanks to several posts I now understand what Recall (Flash) does at
the exchange. For the time being I have accepted that I cannot
acoustically couple a Recall/Flash but I still would liked to send the
appropriate sequence of tones after the Flash to enable automatic call
back. I have, so far, failed. The Flash is not the problem since
automatic call back works if I use the phone to key in the *37# and
press dial.

Re: How do you say "Recall" to a telephone?

<http://telstra-fixed.custhelp.com/cgi-bin/telstra_fixed.cfg/php/enduser/std_adp.php?p_faqid11%54&p_created11%11370527&p_sid=v_z-edWh&p_lva=&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9MyZwX3Byb2RzPTAmcF9jYXRzPSZwX3B2PSZwX2N2PSZwX3BhZ2U9MSZwX3NlYXJjaF90ZXh0PXJlY2FsbA **&p_li=&p_topview=1>

Nope.
Yes, its a timed line break.

Its a lot simpler to just dial the number
again when you have the dialing automated.

Re: How do you say "Recall" to a telephone?
finger to keyboard and composed:

LOL. An acoustic coupler.

Why not use a modem and a built-in app? Windows 98, for example, has
an app called "dialer.exe". You use the dialer to make the call and
then hang up the modem after picking up your parallel connected
telephone handset.
If you prefer to write your own app, then send commands such as ...
AT DT nnnnnnnn;
or ...
AT DT !*37#;
In the case of my Rockwell modem, the "!" flashes the switch hook for
a period of time defined by S-register S29.
For example, AT S2970% sets the hookflash duration to 700msec.
Listen for modem responses such as "BUSY", "NO DIALTONE", "VCON", etc.
The ATH and ATH1 commands cause the modem to go on-hook and off-hook,
respectively.
If you have a "hardware" modem, then you could probably automate the
dialing procedure using a simple DOS batch file.
-- Franc Zabkar
Please remove one 'i' from my address when replying by email.

Re: How do you say "Recall" to a telephone?

The 'recall' function is commonly referred to as 'hook flash' where the line
is dropped and picked up within a short period of time. There probably is a
way to send some sort of command to the exchange hardware that tells it you
want to initiate the same function as if you've flashed the line, but
Telstra probably would do their utmost to make sure nobody can find out
about it. 8-)
Craig.
--
SUN RIPENED KERNELS - Surplus Sun Microsystems Equipment, Parts + Accessories
Waterfall, NSW, Australia - Operated by Craig Dewick - Founded in 1996
SUN RIPENED KERNELS - Surplus Sun Microsystems Equipment, Parts + Accessories
Waterfall, NSW, Australia - Operated by Craig Dewick - Founded in 1996
We've slightly trimmed the long signature. Click to see the full one.

Re: How do you say "Recall" to a telephone?

I believe there are two standards for the duration of the
hook-flash, and the Australian one is between 100-500ms.
The other system is under 100ms, which was all that was
supported on one old (non-approved) phone we bought. I
used to simply bump the hang-up button instead, until we
replaced it with a legal phone.
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