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A dry loop is an unconditioned leased pair of telephone line from a telephone company. The pair does not provide dial tone or battery (continuous electric potential), as opposed to a wet pair, a line usually without dial tone but with battery.
A dry pair was originally used with a security system but more recently may also be used with digital subscriber line (DSL) service or an Ethernet extender to connect two locations, as opposed to a costlier means such as a Frame Relay. The pair in many cases goes through the local telephone exchange.
Wet pair naming comes from the battery used to sustain the loop, which was made from wet cells. The wet pair was the one drowned into the battery.
Many carriers market dry loops to independent DSL providers as a BANA for Basic Analog Loop or in some locales PANA for plain analog loop, OPX (Off Premise Extension) line, Paging Circuit, or finally LADS (Local Area Data Service).
In the United States, these circuits typically incur a monthly recurring charge of $3.00 per 1/4 mile (approximately), plus an additional handling fee of around ($5–10).
In Canada, a CRTC ruling of 21 July 2003 requires telcos (such as Bell Canada) permit dry loop and some companies do provide this service. Naked DSL is currently provided by third-party DSL (Digital Subscriber Line) vendors in the provinces of Ontario and Quebec, but incurs an additional dry loop fee (often $5 or more monthly, depending on the distance from the exchange). There is not yet widespread adoption, as this extra fee often renders dry-loop DSL more costly than comparable cable modem service in most locations. A Bell Canada "dry loop" DSL connection does supply battery, but the underlying phone line is non-functional except to call 958-ANAC, 9-1-1 or the 310-BELL telco business office.