3 ms·
From what I recall (and this could very well be apocryphal), the pauses were what was patented. Non-Hayes modems still reacted to +++ but didn't need the pause.
by danielweber 14y ago
From what I recall (and this could very well be apocryphal), the pauses were what was patented. Non-Hayes modems still reacted to +++ but didn't need the pause. So if you could trick their software into sending "+++ATH;ATDT911" you would make them call 911.
I'd love confirmation or denial of that patent thing.
- ChuckMcM 14y agoFrom the wikipedia page (so take it with a wikipedia sized grain of salt :-) "Hayes had patented this concept in 1985 in patent #4,549,302, the Modem With Improved Escape Sequence With Guard Time Mechanism, generally referred to as the "Hayes '302 patent". Hayes licensed the guard time to other manufacturers for $1 a modem – a charge which competitors derisively termed the "modem tax". A number of manufacturers banded together and introduced the Time Independent Escape Sequence, or TIES, but it was not as robust as Heatherington's system and never became very successful."