This object may only be successfully set on a master device.
When this object is set, the local unit's test mode is
defined by these values when set:
1 - Normal operation
3 - Self test mode
4 - PROM check test
5 - External RAM test
6 - DS1 loop test
7 - MUX-DMUX test
9 - Analog loopback mode
13 - Transceiver mode
When getting this object, the value returned represents
the last value this object had been set to.