Not OP but it sounds like the echo cancellers were fine, the interconnect to the switch was misconfigured. Rather than sending both channels of audio to opposi

Not OP but it sounds like the echo cancellers were fine, the interconnect to the switch was misconfigured. Rather than sending both channels of audio to opposite ends of the same call, one channel got directed to the next call. The funny thing is that if everyone played along they could have had a mean game of telephone going.