The SONAbeam? E Series fills a need in the market for free space optics solutions that are compact, economical and carrier-class. The SONAbeam? E Series includes two redundant high-powered lasers transmitting at 1550nm within a simple, environmentally-sealed housing and transmits at distances from 50m to 4600m (160 ft to 2.9 mi). Interchangeable interface cards allow customers to quickly and inexpensively ramp bandwidth or switch protocols. The interface cards support NxT1/E1, 10/100 Ethernet, E3/DS3, STM-1/OC-3 protocols or datarate transparent transmission and offer the added reliability of clock data-rate recovery (CDR). Additionally, the complete E Series can be managed over Ethernet and is IP addressable.