DIGITAL HIERARCHY
DS 0 - 64 Kbps
DS 1 - 1.544 Mbps
DS 3 - 44.736 Mbps

SONET HIERARCHY
OC-1 - 51.84 Mbps
OC-3 - 155.52 Mbps
OC-12 - 622.08 Mbps
OC-48 - 2,488.32 Mbps
OC-192 - 9,953.28 Mbps
OC-768 - 39,813.12 Mbps

LAND MEASUREMENTS
One Section of Land = 1 Sq. Mile or 640 Acres
One Acre = 43560 Sq. ft. or 160 Sq. Rods
One Chain = 66 ft.
One Rod = 16.5 ft.
One Link = 7.92 in.
One furlong = 660 ft. = 40 Rods

PON STANDARDS
ITU-T G.983
APON (ATM Passive Optical Network). This was the first Passive optical network standard. It was used primarily for business applications.
BPON (Broadband PON) is a standard based on APON. It adds support for WDM, dynamic and higher upstream bandwidth allocation, and survivability.
ITU-T G.984
GPON (Gigabit PON) is an evolution of the BPON standard. It supports higher rates, enhanced security, and choice of Layer 2 protocol (ATM, GEM, Ethernet).
IEEE 802.3ah
EPON or GEPON (Ethernet PON) is an IEEE/EFM standard for using Ethernet for packet data. 802.3ah is now part of the IEEE 802.3 standard.
IEEE 802.3av
10GigEPON (10 Gigabit Ethernet PON) is an IEEE Task Force for 10Gbit/s backwards compatible with 802.3ah EPON. 10GigEPON will use separate wavelengths for 10G and 1G downstream. 802.3av will continue to use a single wavelength for both 10G and 1G upstream with ATDMA separation.