Indicates whether a Test TLV or Data TLV is included when the size
of the DM frame is determined by the jnxSoamDmFrameSize object.
A value of 'true' indicates that the Test TLV is to be included. A
value of 'false' indicates that the Data TLV is to be included.
If the frame size object does not define the DM frame size
the value of this object is ignored.
This object can only be written at row creation time and cannot be
modified once it has been created.