The GDW-11 is a GSM/GPRS modem designed for industrial applications that can be used on 900 and 1800 MHz GSM networks.The modem requires a SIM card to provide connection to a network service provider. The modem contains an enhanced TCP/IP stack to allow GPRS (General Packet Radio Service) connections to be made seamlessly and reliably ensuring maximum availability of the GPRS connection.

If the GPRS connection is broken the modem can automatically re-establish the link. Another enhanced feature in the modem includes the ability to make a CSD connection or send an SMS message when the DTR signal is activated, allowing the modem to be used in applications where the connected device has no intelligence to initiate a call using AT commands. If a PIN number is used by the network, this can be stored in the modem to ensure the availability of the modem after a power failure.The modem can also periodically re-register with the network, this is required as some networks will deregister a SIM that has not moved or been active for a period of time. 
        
    GSM 900/1800 MHz
    Extended temperature range –25°C to +50°C (–13 to –122°F)
    GPRS, class B, class 10
    DTR triggered -dialling and SMS
    Up to 11 data bits
    8 x LED indicators
    Speed CSD up to 14.4 kbit/s, GPRS up to 85.6 kbit/s
    Speed serial: 300 to 115.2 kbit/s
    Galvanic isolation for power supply
    TCP/IP Stack
    RS-232 interface