Proposed revision parts call import phone vehicles ("FeTap", "Siemens", "TriTel", "Philips") and their adaptation to coordinate ate. On the PBX coordinate system type ATSC-100/2000 when the call signal (call) these devices are either not ring at all or slightly "pozvanivaya" during the operation voltage of the inductor. It was found that if the frequency "inductor" below 30 Hz, these the phones do not ring. And the frequency inductor for ATSC is 25 Hz.
In the study of ring parts SHE revealed that all these the devices contain call chip type SAA1092-2 or the company Telefunken analog U4076B.
On the PBX European countries frequency inductor is 50 Hz. The chip contains a function switching frequency accept call signal (up to 30 Hz and above 30 Hz).
In the telephone these chip pin 1 not involved that corresponds to the frequency ringing signal of 50 Hz. When finalizing the author joined pin 1 of the chip with pin 4 (common wire). After that the phone began to ring normally at any time and on any PBX the coordinate system.
The author modified more than 30 vehicles, and they all work fine.
On the scheme call THAT part revision is a switch SA2. When the open-loop button THAT works with the inductor with a frequency of more than 30 Hz, and when closed is less than 30 Hz.
Author: I. Shmorhun; Publication: www.cxem.net