This read-only object is the index (1 to 4) for the demodulator to which a row of alarm-mask settings applies. On a multi-demodulator CDD-564, this index lets each demodulator's alarm masks, such as AGC, Eb/No, or LNB, be configured independently, so masking a nuisance alarm on one demodulator doesn't inadvertently silence the same alarm type on the others. An admin who wants to mask the Eb/No alarm only on a demodulator known to run with a permanently marginal signal would walk the alarm mask table to the row keyed by this index for that specific demodulator before changing the mask setting.