Low price m2m 2G 3G dual band GSM GPRS RS232 USB interface 1 port modem for STK  bulk sms IMEI change
GSM GPRS GPS modem Function:
 m2m 3G GPS  GPRS modem at commands GSM data logger input output modem 
Dual-band GSM external modem
EGSM900/1800Mhz or EGSM900/1900MHz
Small size and aluminum shell shock
Install and us, connect Internet instantly
Has been through all the technical standards certification
Voice, messaging, fax and data transmission of GSM Phase2 +
Designed for a specific application of the AT command control system
 
GSM GPRS GPS modem Technical Specification

Modem4G LTE FDD ModemModule  (Optional)(1) Quectel EC20 (2) Quectel EC21(3) Quectel EC25Interface(Optional)(1) RS232 +Min USB (2) RJ45 + RS232 + Min USBWorking Frequency  (1)EC20 -E     FDD LTE: 850/800/900/1800/2100/2600 MHz                         UMTS:  850/900/2100 MHz                         GSM: 850/900/1800/1900MHz (2)EC20 -A     FDD LTE: 700/850/1700/1900 MHz                         UMTS: 850/1700/1900 MHz                         GSM: 850/1900MHz (3)EC20 -C     FDD LTE: 900/1800/2100 MHz                         TDSCDMA 1900/2100 MHz                          UMTS: 2100 MHz                          GSM: 900/1800MHz (4)EC20 -CE    FDD LTE: 1800/2100 MHz                          TDSCDMA: 1900/2100 MHz                          WCDMA:  2100 MHz                           GSM: 900/1800MHz(1)EC21 -E      FDD LTE: 800/850/900/1800/2100/2600 MHz                          WCDMA:850/900/2100 MHz                          GSM: 900/1800 MHz (2)EC21 -A      FDD LTE:700/1700/1900 MHz                          WCDMA: 850/1700/1900 MHz                          GSM: 900/1800MHz (3)EC21 -V      FDD LTE: 700/1700 MHz (4)EC21-AUT   FDD LTE: 700/850/1800/2100/2600 MHz                            WCDMA: 850/2100MHz  (5)EC21-AUTL FDD LTE: 700/1800/2600 MHz(1)EC25 -E       FDD LTE: 850/800/900/1800/2100/2600 MHz                           WCDMA: 850/900/2100MHz (2)EC25 -A       FDD LTE: 700/1700/1900MHz                           WCDMA:  850/1700/1900MHz                           GSM: 900/1800MHz (3)EC25 -V       FDD LTE: 700/1700 MHz (4)EC25 -AUT   FDD LTE: 700/850/1800/2100/2600 MHz                            WCDMA: 850/2100MHzOperating SystemLINUX, MAC IOS,VISTA,XP,WIN7,WIN8,WIN9,WIN10,WINDOWS

  GSM GPRS GPS modem Function 
- Voice function call emergency telephone
Voice Codec: full-speed, full-speed and semi-enhanced rate (FR / EFR / HR)
DTMF functions (DTMF)
- Data function   Non-synchronous data circuit   Transparent and non-transparent to the highest standards 14400 bits/s
the third category automatically fax (Class1 and Class2)
MNP2, V42bis
- Short message service text and PDU peer-to-peer (MT / MO)  district Broadcast
 
GSM GPRS GPS modem Interface
-   RS-232 connections through a small mouth and Sub-D15 connector plugs audio
 
Interface support:
-   at command used for the remote control (GSM07.07 and 07.05)
-   Link bit rate from 300 to 115,200 bits / s
-   Automatic bit rate (300 to 38,400 bits / s)
-   - through micro - FIT4 Plug power connector
-   - SMA Antenna Interface
-   - Down the SIM card memory