The SX20 Plus CODECs do not permit the audio protocols to be forced, hence we were only able to carry out detailed tests on G.722.1 and AAC-LD audio coding.

Test 1: Frequency response (-3 dB)

(Insert -6 dB signal at local site, measure at remote site)

Test 2: Headroom (measured on AAC-LD signal coding)

Insert increasing amplitude 1 KHz tone at local site, monitor for overload distortion at remote site

Overload occurs at:                  +12dBm

Test 3:  Audio level

(Insert -6dBm 1KHz tone at local site, monitor received level at remote site.)

As the audio output level is affected by the volume control this test was not carried out.

Test 4: Echo Cancellation

Setup     The echo canceller is fully automatic in operation. The quality of echo cancellation and doubletalk from the system was excellent.