How to connect Icon BTD12 busy tone fender to Cisco SPA8800?

Question

Asterisk

In an organization, IP telephony is implemented as follows. Several telephone numbers (lines) are used from the city PBX. The Cisco SPA8800 gateway is installed and configured, the Asterisk IP telephony server (FreePBX add-on) is deployed and launched. The total number of subscribers is about 100.
Recently, there have been a lot of problems with the fact that the moment of the end of the conversation is incorrectly determined (there is no recognition that "the phone is on-hook"), as a result, subscribers are faced with the problem that "all lines are busy".
All installations and settings were done by the previous employee. There is no way to check the gateway settings - it slows down a lot, you can only perform authorization in the web interface (then it works very slowly, you can’t get to the Voice / Line settings). Previously, I bought a rebound detector - Icon BTD12, now I need to install it.
Tell me - if there are any nuances in connecting the Icon BTD12 to the Cisco SPA8800? Are any extras needed? settings. It is clear from the instructions that the device is configured on all 12 lines for a 425Hz busy signal.
Most

Answer 1

In a line break according to the scheme. The fender should, when a signal is detected, "turn over" (connect vice versa) the wires of the line. This is the standard behavior of the line, and, most likely, Cisco expects such a release.