1,20門總線電話，布線只需二根且不分極性

2,主分互叫；分機(jī)摘機(jī)即通話，主機(jī)顯號(hào)
3,可三方通話
4,通話時(shí)自動(dòng)啟動(dòng)數(shù)字錄音

2-Bus Control Telephone Panel(Wall-mounted structure)
1, Only a twisted-pair wire without polarity is needed.
2, A total of 20 extensions can be provided for the main phone.
3, Each extension can call the main phone without dialing. And the main phonecan call any of the fitted extension too. What’s more, the extension numberdisplays when it is calling.
4,The systems can start digital recording when communicating.