I have collected a few antique phones over the years including a neat 3-slot payphone. The antiques are rotary dial phones which work well with my Grandstream HT-502 VOIP boxes but not with any of Obihai's offerings.
I recently purchased a DialGizmo pulse to tone converter and am using it with an Obi200. I thought I would post a few notes on how to make it work.
Note 1: The Obi defaults to a very short dialing interval. You can dial the rotary fast enough but it is difficult. The Obi interdigit interval needs to be increased. In the physical interface section phone port, add S4 to all the entries. ([1-9]x?*(Mpli)S4|[1-9]S4...and so on) This will give you 4 seconds between digits.
Note 2: I had to increase the max current from 20ma to 30ma in order to get the dial hold feature of the DialGizmo to function correctly. This is also done in the physical interface phone options.
Note 3: I wanted to locate the DialGizmo at the Obi instead of at each phone. This works but introduces a slight hum on the line. I did a ton of experiments to try to eliminate the hum but the only thing that works is changing the Obi power supply to a 12V regulated linear supply or an ITE rated switching supply. FWIW, the hum is very slight but I like the line quiet.
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Anyway, I searched the forum and found little reference to using a pulse to tone adapter so hopefully this will help others who might want to go this road!
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Wish List:
1. I would like for the Obi to support pulse dialing like the Grandstream HT-502 or better yet, incorporate the dial hold function of the DialGizmo to allow the # and * to be dialed.
2. I would like the Obi to incorporate the caller name in the caller ID data if the caller is in my GV phone book. GV apps have this capability so Obi should be able to do it in their adaptation.
