Circuits and methods for a low voltage pre-distortion circuits that provide a temperature and logarithmically compensated voltage such that a gain change of a variable gain amplifier is linear in dB and has a reduced temperature dependency. Divergence problems in echo cancellers cause considerable problems in interactive caller response systems, they cause less problems if all parties to a call are human. The particulate monitor also includes a real-time measuring device positioned at least partially within the housing and in fluid communication with the air passageway and a particulate collection device positioned at least partially within the housing and in fluid communication with the air passageway. The method further includes communicating the first document and the second document in a reliable manner over a network to a next destination. The toe strap is also preferably a quick-release ratcheting strap, and is preferably attached in existing toe strap mounting holes.