Da quello che ho trovato, credo si tratti del diametro riferito ad una scala standard usata negli USA (AWG = scala americana dei diametri dei fili metallici.)

hope it helps

allowing the service to run on longer loops without repeaters, for example, 3.7km (12,000ft.) on *
.5mm (24 gauge) wire *. HDSL uses more advanced modulation techniques than T1 and E1. HDSL
does not allow standard telephone service over the same line.
http://www.laser.dist.unige.it/Repository/Reti2-V/Accesso/xD...

WIRE GAUGE
measurement of how large a wire is, either in diameter or cross sectional area. This determines the amount of electrical current a wire can safely carry, as well as its electrical resistance and weight per unit of length. Wire gauge is therefore applicable to both electrical and non-electrical wires, thus it is important to electrical wiring and to structural cable.
http://en.wikipedia.org/wiki/Wire_gauge

American wire gauge, AWG (of wire diameters) (mech.), scala AWG, scala americana dei diametri dei fili metallici.
Birmingham wire gauge, BWG (of wire diameters) (mech.), scala BWG, scala di Birmingham (dei diametri dei fili metallici).
Marolli, Hoepli

American wire gauge (AWG), also known as the "Brown and Sharpe" wire gauge, is used in the United States and other countries as a standard method of denoting wire diameter, especially for nonferrous, electrically conducting wire.
AWG = 24 0.0201 0.5106 49.75 19.59 0.40 0.205 84.219 25.67 1/0.5, 7/0.2, 30/0.1
http://en.wikipedia.org/wiki/American_wire_gauge

24 GAUGE WIRE Copper
105 feet
http://kitkraft.biz/catalog/Wire-p-1-c-78.html

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Note added at 5 days (2007-09-01 16:52:53 GMT) Post-grading
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>Grazie
grazie a te e buon week end