1.GSM 900/1800mhz (850/1900mhz optional); 2.Support normal fax port and ext. port,can connect to a fax machine. 3.Support GSM virtual network. 4.Attached small keyboard to input more conveniently. 5.Ringing even in off hook mode. 6.128*64 LCD with green background light showing four lines information. 7.Support keyboard locking. 8.Support speed dialing by one key. 9.Long-distance call locking (PSTN only). 10.Support carrier locking. 11.Automatically add IP access number ahead of long distance calls. 12.Short messages. 13.Calls records. 14.Incoming caller ID. 15.Restore history records of calls. 16.Receiving calls in hands free mode and hanging up automatically when finishing the call (GSM only) 17.Internal or external antenna. 18.Support up to 18 types of ring tones. 19.Support management through both SMS and serial port. 20.Intelligent power management. 21.Displaying battery level and signal strength. 22.Using industrial wireless module.