A loss of signal assert and de-assert level programming mechanism in an
optical transceiver coupled to a host computing system. A control module
is connected to the host so as to receive the programmable loss of signal
level. A post-amplifier detects when the receive power drops below a loss
of signal level. However, in this case, instead of the loss of signal
level being static, a loss of signal level adjustment mechanism changes
the loss of signal level detected by the post-amplifier as directed by
the programmable loss of signal level received from the host. The loss of
signal assert and de-assert levels may be calibrated by comparing receive
power to the threshold for assertion and de-assertion of the loss of
signal.