Automated Telephone PBX System This CS416 PBX system is an ideal telephone system for small offices and home offices. It is very easy to install and use. It has all the standard features comparable to those expensive PBX systems in the market. It works with your current analog phones and you do not need to spend extra money to buy proprietary telephones to work with the PBX.Installation is simple, no special tools, test equipment or technical skills is required. The unit has been programmed to work automatically out of the box. Photos show: Work with our PH206 PABX Office Phone If you also are interested in this PH206 Multifunction Office Phone( can be acted as the main /operator phone),please click this link below to get more information: https://www.aliexpress.com/item/1005003397149209.html CS416PBXFeatures CO. line 4 Ext. line16 Multiple Communications Line Normal transform power Power Failure Transfer External Line Caller ID ( but don't support intercom caller ID ) Door phone ( support our own 2 door phones,but don't support electric door locker!) Auto-Attendant(DISA-120s four paragraphs) Internal Music on holding Remote programming Memory protect while power off Auto/Operator mode System Password Flexible Ext. No. Assignment Multiple Dial-Out Mode External line group Call Duration Control Call Pickup Outgoing Call Transfer Call Transfer Call Forwarding Flexible coding(change Ext.No.) Do Not Disturb Automatic EX Reporting Flash Time Choice Ringing Assignment Call Restriction Three Way Conference Call all extensions Specific Co line dialing Ring identify C.O line Booking C.O line Reservation Operator setting C.O Monitor Technical parameters Extension: 16 External line: 4 Commucation line: 7 Power supply: AC 110 or 220V Power: =<40W Storage battery pressure: DC 48VCharge current: =<30mA (Optional) [Remarks]: CS416 comes with 4CO landlines ports and 16 internal extension ports, which can work with maximum 4 telecom landlines and 16 analog/regular/common telephones to work, it doesn't support digital phones and also not be compatible with Pana_sonic phones!