What is a dry pair ?
A dry pair is a pair of telephone wires that does not have regular voice on it, thus no dialtone. It is a dedicated line usually used for internet. Dry pairs are now found in SDSL, ISDN, IDSL, or a T-1 type service. The following clarification submitted by NickNielsen It is true a dry pair does not have dial tone, but a dry pair does not have any battery on it by definition. A wet pair has battery present on it. There are several applications for a dry pair. A T1 is not a dry pair in the sense used. Indeed, a T1 opposite of the customers side of the network is hardly ever dry. It will commonly have 120VDC which is used to power remote repeaters for the T1 circuit depending on its length. The T1 network interface will isolate this high voltage and bring the signal to a much safer level. This is the reason the CSU/DSU has a Line Build Out (LBO) setting maximum of just over 600′ from DMARC. It may not reliably work past that distance from the CSU/DSU. This point might have been confused w
