The Fluke Networks' 10113000 Phone Line Modular Adapter is for telephone system testing with a standard butt set. Four clearly marked contacts for error-free termination with phone jack and riveted sp...
"Based on SIP, the Cisco SPA 303 3-Line IP Phone with 2-Port Switch has been tested to help ensure comprehensive interoperability with equipment from voice over IP (VoIP) infrastructure leaders, enabl...
Amplicomms Universal Line Amplifier for Corded Phones If your hearing isn't what it used to be, this compact battery-operated Phone Amplifier is the ideal solution. You can hear the caller's voice lou...
AdvantagesFree (or cheap if you buy the full version)
AdvantagesExcellent down to earth teaching.
DisadvantagesNot for everyone.
Disadvantagesboring in places and predictable ending