The value of this object is used to specify the Tx Test Pattern in an IMA group loopback operation. A value in the range 0 to 255 designates a specific pattern. The distinguished value of -1 specifies that the implementation may choose the value. In this case, the implementation may also choose the value of 'imaGroupTestLinkIfIndex'.

It is recommended that the specific value 255 not be used for testing, since by (R-137) the IMA interface is required to transmit 0xFF (i.e., 255) when the incoming test command is inactive or the test link is not detected, and thus it cannot be established for certain whether 255 was received due to an actual loopback operation or due to the normal operation of an IMA that is not performing (or else cannot perform) the test pattern procedure.