OLT is the endpoint hardware device/terminal equipment in a passive optical network (PON). It sends Ethernet data to the ONU, initiates and controls the ranging process, and records the ranging information. OLT allocates bandwidth to the ONU and controls the starting time and the transmission window size of the ONU transmission data.
The OLT contains a central processing unit (CPU), passive optical network (PON) cards, a gateway router (GWR) and voice gateway (VGW) uplink cards. Each OLT can have a few or many dozens of PON cards. It can transmit a data signal to users at 1490 nanometers (nm), and receives the ONT transmission of the 1310nm laser data signal. That signal can serve up to 128 ONTs at a range of up to 12.5 miles by using optical splitters.
- A downstream frame processing means for receiving and churning an asynchronous transfer mode cell to generate a downstream frame, and converting a parallel data of the downstream frame into a serial data thereof.
- A wavelength division multiplexing means for performing an electro/optical conversion of the serial data of the downstream frame and performing a wavelength division multiplexing thereof.
- A upstream frame processing means for extracting data from the wavelength division multiplexing means, searching an overhead field, delineating a slot boundary, and processing a physical layer operations administration and maintenance (PLOAM) cell and a divided slot separately.
- A control signal generation means for performing a media access control (MAC) protocol and generating variables and timing signals used for the downstream frame processing means and the upstream frame processing means.
- A control means for controlling the downstream frame processing means and the upstream frame processing means by using the variables and the timing signals from the control signal generation means.