!!! Overview
[{$pagename}] is a signalling [Protocol] for [Land Lines] in which a party gets a dial tone by closing (shorting) a DC current loop.


[{$pagename}], the electrical loop between your telephone and your [Telephone exchange] is normally open. When you pick up the telephone handset, it causes a circuit to be closed — creating a loop.

[{$pagename}] signaling is normally used [POTS] ([Public Switched Telephone Network]) lines and key-switch systems.



!! More Information
There might be more information for this subject on one of the following:
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* [#1] - [Loop Start|http://www.tech-faq.com/loop-start.html|target='_blank'] - based on information obtained 2019-08-23