For the ONYX or USBClient software to record calls from an IP phone,
we need to tap the line (analogue) or the base of the phone.
Mitel is an IP switch therefore no analog line. The only option is
to tap the base of the phone. If the base of the phone has the RJ9
connector for the curley cord and the flat phone cable (with
standard wiring) it should work.
If the phone has a RJ11 connection, you must convert it on to RJ9.
The RJ9 has 4 wires. We use the inner pair(speaker) outer pair(mic)
standard. The RJ11 has 6 wires. We only use the inside 4 wires.
You will need to replace the cable connectors on the USB tap side
to RJ9(as per tap connection) and the base of the phone side to
RJ11(as per hand set connection). The curley cord goes into the tap
and the flat phone cable into the handset.