The Loop Emulation Sevice for Public Switch Telephone Network

It is a protocol that supports the delivery of POTS over the loop emulation service which helps to convey analog supervisory signaling states is commonly used by IWFs (interworking functions to support CCS ( Common Chanel Signalling). To avoid the signaling analog line states this protocol uses the simiar message set as the V5-PSTN (ETSI EN 300/324-1) thus covering the risk due to the variations seen in individual national implementation of analog POTS.