Features 1??With Screen: GSM caller comes with a screen so you can clearly see the data, reverse polarity signals, and can be connected to billing devices or use computer billing devices. 2??Support Voice Service: Use this terminal to make local, national and international calls by connecting to a regular wired desk phone and a standard SIM card. 3??Strong Signal Reception: GSM ID dialer is easy to install, simple to operate, strong signal reception, clear call settings, long service life and stable performance. 4??Multi Group IP Setting: Fully automatic IP function, multi IP setting, using GSM 4G cell phone SIM card, no change of original dialing habit, easy to use. 5??Widely Used: GSM caller is suitable for remote villages, mountainous areas, houses with weak signals, public telephone stores, offices, telemarketing, ships and other mobile places. Specification Item Type: Fixed Wireless Terminal Material: ABS Product Size: LxWxH, Approx. 16.2 x 10 x 3.8cm / 6.4 x 3.94 x 1.5in ( Manual Measurement, Slight Error May Exist) Installation: No need to invest in ground wired line, support 4G/GSM cell phone SIM card. Easy installation Voice Services: Support International and Domestic, Local, Fixed/Mobile Voice Services Operation: Do Not Change the Original Dialing Habits, and the Operation Habits of Ordinary Telephone Landlines Are the Same Antipodal Signal: With Antipodal Signal, Can Be Connected to the Fare Register or Use a Computer Fare Register. Watchdog: Inbuilt Watchdog Circuit on Duty. Automatically Detects the Running Status of the Device, and Restarts Automatically when a Fault Occurs No Error: DTMF Transmission Mode, the Caller ID Error is 0 IP Function: Automatic IP Function, Multiple Groups of IP Settings Calling Party: Calling Party IP Prefix of Fixed Long Distance Calling, Such As 17951, 17911, and 193, etc. Permission Setting: Permission Setting of Incoming Call of International, National, and Local Calls Code Preset: Preset Local Area Code, Local Number Segment, and Forbidden Number or Number Segment Encryption Settings: Such As PIN, PUK Encryption Machine Card Locking Function LED Lights: Display Signal, Standby State, Working State and Other Information Caller ID: Yes Interface form: RJ11 TDD: B38/B40/B41 WCDMA: B1/B8 GSM: B3/B8 EC25 AF: LTE FDD: B2/B4/B5/B12/B13/B14/B66/B71 WCDMA: B2/B4/B5 LTE FDD: B1/B2/B3/B4/B5/B7/B8/B28 LTE TDD: B40 WCDMA: B1/B2/B5/B8 GSM: B2/B3/B5/B8 Recording Function: None Signal Sensitivity: