This read-write TruthValue controls the direction of the Continuity of Transmission (COT) tone sent in a 2-wire to 4-wire arrangement, where VISM responds to a 2010Hz go tone with a 1780Hz tone or vice versa depending on this setting. An admin cares because getting the tone direction wrong will cause continuity tests initiated via the M:conttest mode to fail even though the underlying circuit is healthy. For example, a technician setting up VISM to interoperate with a specific central office continuity test procedure would set this object to match whichever tone direction that office expects.