Our Sandwich Jack provides an extra modular jack when installing a wall phone. It's like the meat in a sandwich, and goes between your wall phone and your wall jack.
It installs easily over most existing wall phone jacks (equipped with mounting lugs), and you don't need to take your phone apart or install any new wiring.
The extra jack can be used for connecting a modem, answerer, Caller ID display, recorder or other accessory, or a second phone.
All four wires are live in both jacks, so it's suitable for both one-line (RJ11) and two-line (RJ14) equipment.
Your wall phone will work normally, even if nothing is plugged into the extra jack. UL certified.
NOTE: This can NOT be used with most "system" phones.