The E-10 and E-20A can be connected directly to a C.O. line or analog PABX/KSU station when used in conjunction with a Hot-Line Dialer or programmed ring down circuit. The E-10 and E-20A can also be used with Viking’s DLE-200B ring down circuit. When the "Call" button is pressed, the E-10 or E-20A will come off-hook and will remain off-hook until CPC is detected or the pre-selected timeout has elapsed (adjustable from approximately 6 seconds - 5 minutes). During this time the user may converse handsfree. For outdoor or harsh environments, the E-10 and E-20A are available with EWP (Enhanced Weather Protection) . EWP products feature rubber gaskets and boots, hand soldered silicon sealed connections, gel filled tip and ring connectors, as well as urethane potted circuit boards with weather sealed, field-adjustable trim pots and DIP switches for easy on-site programming. Note: For a programmable phone with a built-in dialer see the E-30 Applications Commercial, industrial and residential door security Door or gate communication Truck stop/gas station fuel island communication Business delivery entrances Use in conjunction with a Viking Hot-Line Dialer on C.O. lines or analog PABX/KSU stations Use on any programmed ringdown circuit of an analog PABX/KSU station Features Telephone line powered Weather resistant Adjustable microphone and speaker volume One year warranty Made in the USA E-10 Features: Vandal resistant, black powder painted, aluminum face plate with mounting gaskets Flush mountable using included rough-in box Surface mountable using the VE-5x5 surface mount box E-20A Features: Ash colored, impact resistant, UV stable, plastic chassis Surface mountable only E-10/E-20A Features: Call timer on/off switch Adjustable time out to limit prank calls and false alarms (approximately 6 seconds - 5 minutes) Auto-answer feature allows remote monitoring (can be disabled) Optional EWP (Enhanced Weather Protection) Specifications Power: Telephone line powered (20 VDC/18mA minimum) Dimensions: E-10 - Overall - 127mm x 127mm x 57.2mm (5.0" x 5.0" x 2.25") Plastic electrical box - 102mm x 102mm x 57mm (4" x 4" x 2.25") E-20A - 120mm x 70mm x 35mm (4.75" x 2.75" x 1.38") Shipping Weights: E-10 - 1.59 kg (3.5 lbs) E-20A - .91 kg (2 lbs) Environmental: 0° to 32° C (32° to 90° F) with 5% to 95% non-condensing humidity Connections: (1) RJ11 jack