4 with 16 small telephone exchange (caller ID type) 

 Four of the switches can extend into 16 outside telephone extensions, each extension has an outside call while significant, 
 At the same time use all the extensions to allow non-interfering. Call quality is not outside the distance limit, regardless of access 
 How many extensions will not have any impact on the bureau. Extension can be telephones, fax machines, answering machines 
 Any telecommunications products and computers, the inherent function of the extension is still valid. The switch provides computer 
 And manual shift mode two, the computer mode you can shift your telephone number, name or unit name of the record 
 Into the switch, suggesting that foreign, to establish a corporate image, improve efficiency, savings in staff expenses 
 Purposes. Improved anti-jamming, anti-lightning and theft hit performance, the power to adapt to range up to 180 volts to 240 volts, 
 Harsh environments. Beautifully thin design, with all kinds of working status indicator, make it elegant, 
 Second to none.