I understand all the concepts behind IVR systems.

I've never been able to quite understand why pulse dialing can't be used with IVR systems. Tones are obviously sent to the other party, but a pulse is essentially a quick disconnect and connect of the circuit, so wouldn't the other party be able to somehow sense that disruption? Today, most phone companies don't use Strowger switches - they use digital switches meaning they are already using computers to "read" the pulses being sent down the line, so I don't understand why they couldn't just 'pass' those pulses on to the called party. The only answers I've seen online is "it costs too much" which is just ridiculous because pulse dialing can be done with purely mechanical equipment and there is no reason a computer cannot listen for pulses the same way it listens for tones.

Am I missing something else here? I am assuming that pulses are detectable by the called party and that the equipment reading pulses is digital (basically a computer of some sort). I'm not sure why pulses can't be passed on from the central office in the same manner as DTMF tones, especially since my understanding is that the other part can hear audible clicks on the line if you spin the dial or rapidly depress the switchhook when on a call.

In fact, I have just confirmed this. I can hear VERY LOUD pulses through the receiver when the calling telephone's dial is released, just as one would expect.

Note: I am not referring to the use of the * and # keys, which you obviously can't emulate when pulse dialing; but rather how any digit cannot be pulse dialed and used with IVR systems.

IVR = Interactive Voice Response (i.e. Press 1 for X, Press 2 for Y, Press 3 for Z, etc...)

I have two Panasonic PBX systems at home and they both automatically convert pulses to tones when an outgoing call is made. So the telephone company could easily do the SAME thing with absolutely NO additional cost. My PBXs make it seem like pulses and tones are equally easy to forward to the caller (I've tested and tones and pulses can both be heard by the caller) so systems should be smart enough to recognize simple pulses in addition to tones.

Obviously, * and # could not be simulated using pulses but you can't have everything...

From previous comments, I've gotten the vibe that companies just choose not to support it. But given the telephone company can recognize pulses using the same equipment, I am not sure why the same cannot be said for customer premises equipment that listens to keypad input. Regardless of whether or not it is or should be supported, is this feasible and possible??

  • \$\begingroup\$ In band signaling is easier to listen to. DTMF decoders can work with more noise without risking disconnect. Simpler hardware. Various guesses here. Someone should provide a verifiable answer soon. \$\endgroup\$
    – Passerby
    Commented Mar 14, 2017 at 4:04
  • 2
    \$\begingroup\$ If you MUST use acronyms.. please expand it once in your question. Not everyone knows what IVR means but may know why you can or can't do what you are asking. \$\endgroup\$
    – Trevor_G
    Commented Mar 14, 2017 at 5:37
  • \$\begingroup\$ One reason is probably to do with the way the "second line" functions work. That is, to switch lines you make a quick disconnect. Would be the same as dialing a 1 with a rotary I believe. If that was surmountable, I doubt they would pass it on as pulses though, more likely they would translate it back into tones at the exchange. \$\endgroup\$
    – Trevor_G
    Commented Mar 14, 2017 at 5:42
  • 1
    \$\begingroup\$ Considering that pulse dialing is basically only a historical oddment at this point, I'd assume that most of the things that "could" support it just haven't bothered, because who the heck still uses rotary phones anymore? \$\endgroup\$ Commented Apr 13, 2017 at 22:19
  • 1
    \$\begingroup\$ I like where it says "the evidence doesn't support it but we're going to call it a carcinogen anyway." \$\endgroup\$
    – JRE
    Commented Jun 15, 2017 at 19:06


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