Author Topic: AMAZING discovery on Grandstream HT802  (Read 343 times)

Offline markosjal

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AMAZING discovery on Grandstream HT802
« on: January 15, 2018, 01:25:36 AM »
I have some unlocked Vonage HT802s now running the latest generic firmware.

I was testing a problematic ringer on a Rotary dial AE Styleline on various ATAs and dialed my local echo test . I thought I had disconnected from the echo test and went to dial another number but as I dialed , WAIT, did I hear???

YES! The HT802 converts pulses to tones while in a call. That is to say TONE OVERDIALING WITH A ROTARY PHONE!

Grandstream started by first selling cheap Chinese junk. I still have one of the original Budgettones from years ago which I have always hated.

Grandstream just earned my respect!
Phat Phantom's phreaking phone phettish

Offline AE_Collector

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Re: AMAZING discovery on Grandstream HT802
« Reply #1 on: January 15, 2018, 02:30:39 AM »
I know this isnít your point but.....AE single gong (Styleline) ringers are always an exercise in futility to get to ring properly.


Offline kb3pxr

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Re: AMAZING discovery on Grandstream HT802
« Reply #2 on: January 15, 2018, 02:49:09 PM »
This conversion is actually a side effect to the way DTMF is handled. Any time DTMF audio is desired on the receiving side, the out of band signaling is used to (re-)generate the tone. When pulse dialing is used, your ATA generates the same signal. The echo test server generates the DTMF tone to send back to you when it receives a dialed digit. The echo test server does not care how the digit was actually dialed, it simply assumes that when it receives a dialed digit, you want the DTMF tones back in return. If you had a device on your end that accepted MF signalling, your MF digits would actually come back as DTMF from the echo test.

It's rare, but it also works the other way. Remember, the network only sees digits. If you have an FXS port set to dial using pulse instead of tone, any digit you dial regardless of method (tone, pulse, digital keypad, MF, etc) would be converted to dial pulses.

Watch the ethernet port lights the next time you take your VoIP device off hook. There should be no activity on the ethernet side when you receive a dial tone. If early dial is disabled, you won't see any activity until you are finished dialing.

Offline markosjal

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Re: AMAZING discovery on Grandstream HT802
« Reply #3 on: January 17, 2018, 11:43:52 PM »
I have other pulse compatible ATAs ; unlocked   vdv21 and utstarcom among others. None generate Dtmf on the line at any time . They merely read the pulses and translate that to a sip message with no need to generate a Dtmf tone. Neither of the others do tone while in a  all with a rotary phone.

The Grandstream actually converts pulses to Dtmf or at least to rfc2833 out of band signalling. Result is I hear a tone when using rotary dial and only with Grandstream.
Phat Phantom's phreaking phone phettish