On Thu 24 Oct at 23:50 Poe Lim (3:623/630) wrote to Arthur Marsh:

 AM> When the network echo supressors and echo cancellers 
 AM> can't be disabled, echo-cancelling protocols will have 
 AM> problems...

 PL> Are the cancellors on both end, or one end? The reason I ask 
 PL> is one area in the US had that problem, but elsewhere was okay.

Usually they're at both ends, but there could be situations where more echo
cancellors/supressors are in the chain if there is a 2 wire interface
between different carriers rather than two half-circuits between the
originating exchange and the terminating exchange.

--- msgedsq 2.1