Telephone line powered. Hearing aid compatible amplified handsets. Rotary handset volume control. 1-32 digit programmable speed dial number. Touch Tone and 10/20 pps pulse dialing. Non-volatile E2 memory (no batteries required). Restricts fraudulent calls from hand held dialers. K-1900D/W-2 available in red or ash. Optional Q170600 ringer (Fax Back Doc 845). Operates on a C. O. line or analog PABX/KSU extensions. Ring detection (will not dial on incoming calls). Programmable security code to enter programming mode. Touch Tone programmable. K-1900-6 fits standard 500, 554, 2500 and 2554 set phones.