Siedle BTSV 850-03 សៀវភៅណែនាំអំពីទូរសព្ទឡានក្រុងស្តង់ដារ
Siedle BTSV 850-03 Standard Bus Telephone Operating Instructions for end users Accepting door calls The ringing tones for the front door and apartment door are different. When a visitor presses the door bell, the telephone rings and the mute button…