To verify the model, we measured the complex acoustic admittances of a series of circular tubes as a function of length between 200 Hz and 10 kHz using a three-port acoustic coupler
. The absolute magnitude of the specific acoustic admittance is approximately one.
A "Y"-splitter single-to-dual RJ-11 jack, or an acoustic coupler
that attaches to almost any phone handset, lets the modem communicate audibly with the phone system.
TDDs are special phones that incorporate a standard typewriter key board, alphanumeric display, and an acoustic coupler
and/ or standard RJ-11 jack for network connections.
Equipped with dumb terminals, rotary dial phones, and a contraption called an acoustic coupler
, I would cautiously dial an access number and wait for the electronic "noise" that told me I was inside Dialog's mainframe computers.
I can't remember how the subject came up, but database searching was under discussion, and someone mentioned learning how to search Dialog in library school--a process accessed via telephone and acoustic coupler
When I went to library school, we searched Dialog over dial-up, placing the phone in an acoustic coupler
so we could connect at 300 baud.