Long Range Ethernet Extenders (LREs) use ordinary telephone lines or similar wiring to extend ethernet connections to physically distant locations. In essence, Cisco's LRE equipment creates a small scale DSL network using a PBX or POTS (ordinary phone system) set of phone lines in conunction with an LRE switch and LRE modem 'endpoints'. A typical LRE network will have an LRE switch connecting to a LAN/WAN (like the Cisco 2912-LRE, 2924-LRE or 2950ST-LRE switch, where each switch can support from 8 to 24 LRE endpoint modems) and a set of CPE LREs (terminating LRE device) deployed where ethernet connectivity is needed (hotel room, classroom, office, etc). The terminating device changes the signal back to ethernet, and one or more ordinary ethernet cables can be plugged into the CPE to connect a computer or other device to the network. There are three models of LRE modems - single-port Cisco575-LRE or Cisco576-LRE and the four-port Cisco585-LRE. All these units can be used as free-standing long range ethernet extenders or, for additional functonality, with a Cisco LRE switch. The 575 and 585 are optimized for use with the WS-C29XX LRE switch series, and the 576 is optimized for use with the WS-C2950 LRE switch series.
Cisco discontinued these popular and widely used ethernet extenders because of a chip manufacturers bankrutcy. However, ISPTrader continues to stock and distribute 575, 576s and 585s as well as the LRE switches - and at present is one of the only remaining stocking companies in the U.S.