A much simpler and therefore, inherently CAPEX and OPEX saving form of transport is to do this passive. Here signal generation and signal transport is done within the same equipment, e.g. an Ethernet Switch. Since signal conversion by itself does not add any benefits but only tremendous costs, risk of failure and in the best case only maintains the signal quality (but does not approve it) it is avoided. So instead of using local transceivers and converting their signals in a rather complicated manner via transponder cards to the line transceivers, the line transceivers are directly plugged into the terminal equipment (e.g. the Ethernet Switch). Doing so makes everything but the line transceivers and the passive optical multiplexers obsolete and is therefore, taken out.
It is evident that this mean of transport not only saves >50% of CAPEX by eliminating mandatory parts (chassis, power supplies, transponder cards etc.) but that savings on the OPEX side are even bigger: No transport equipment software (SNMP management) needs to be integrated, operated, maintained and updated, much fewer electronic parts exponentially increase MTBF (Meantime Between Failure) numbers reducing down times and costly maintenances and support services. Last but not least, electric power consumption can be reduced by easily >50%: First of all as there is no extra transport system to power, second, since there is no extra heat generated cooling through air-conditioning can be largely reduced.
As there is no extra monitoring of the transport system, the remaining active parts (the "colored" line side transceivers) are managed via existing monitoring (e.g. SNMP) in the terminal equipment. The passive Muxes, inherently without electric circuits, remain un-monitored like in most active transport solutions anyway. They are in the same manner monitored as the passive ODFs, connectors, patch cables, transport fibers or any other passive element in the network - in an indirect manner.
Apart from CAPEX and OPEX savings aspects a Passive Transport Solution inherently also reduces latency times in the network and will provide a better network performance than the active counteparts.