HATS Audio Testing

[Udaynag Pisipati <udaynag@xxxxxxxxx>]

I am using Head & Torso Simulator(HATS)  type 4128C for testing Audio quality on Bluetooth Headsets and I have a problem with the calibration. This is what I am doing..We create a live PSTN to Mobile phone call and I have all the setup for the signal from landline to reach the HATS ear on the DOWNLINK and also the signal from the HATS mouth reaches the landline back on the UPLINK. I am using Pro Tools LE (software)& Mbox(Hardware) to play and record the signals on uplink and downlink. Now, I have to calibrate the whole setup so that I compare the levels obtained on different mobiles with a reference listening level. I can calibrate the HATS mouth using the reference micorphone supplied by Bruel & Kjaer (we got HATS from them), but then there is the remaining link that the signal passes through to reach 
Mbox.I am looking for a setup to callibrate this whole link and I was wondering if anybody who worked on such a setup or similar setup could help me out. If this is not a question that needs to be posted on this list, please forward me to any other list that I could find some help on.