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The GSM-to-Ethernet (G2S) bridge is a ready-to-use protocol converter that is intended for extending the communications reach of an existing device with a serial interface (RS232/RS485) over a wireless GSM network. For example for out-in-the-field installations of the device.

Original configuration

The configuration consists of an OEM device that has an serial interface (RS485/RS232) and PC that communicates with the OEM device using this interface. The protocol used for serial communications is usually an OEM specific protocol. Which may or may not be encapsulated in TCP/IP packets. (i.e. using SLIP or PPP as a carrier protocol for the OEM data)

A dedicated OEM application that understands this OEM specific protocol runs on the PC.

The OEM application may or may not include support for remote device connections with a PSTN modem or over an intranet/internet using TCP/IP (socket interface)




Figure 1: Original (local) configuration 



Example configurations for remote access with G2S bridge


Figure 2: Dial-in access with analog modem (GSM data)



 Figure 3: Mobile dial-in access with laptop and GSM phone (GSM data)


Figure 4: Direct access via public internet (GPRS)


Note that direct access via the public internet as in figure 4 requires GPRS for wireless communications over a GSM network. GSM data will not do. It also requires support for TCP/IP (socket interface) in the OEM application at the PC side.

With the G2S bridge the serial data protocol is ‘bridged’ transparently between the PC and the OEM device, the GSM network is used as a transport channel to get the data to/from the OEM device.

The G2S bridge supports both GSM data and GPRS as a carrier for the serial communications over a GSM network.

Quick comparison GSM data and GPRS


GSM data


Connection type

Circuit switched

Packet switched

Billing You pay for duration of the connection. You pay for the amount of data that is transferred.
Max speed (baud) 9600 115200 (theoretical), 38400 in real-life
Connection set up time ~ 30 seconds < 1 second ('always on')
Direct access to device via public internet No Yes, if GSM provider binds public IP address to SIM card. (more info)

In general GPRS is usually more cost-effective than GSM data if the device is to accessed frequently (> few times per day) and/or if the amount of data to be transferred is big (> few KB per visit). Contact your GSM provider for more details.

Modem emulation and support for SLIP/PPP as carrier protocol at serial side are optional.

Note that the G2S bridge is intended user-initiated for dial-in connections to the device. If device-initiated dial-out connections are (also) required then customizations to G2E software may be required. In that case contact us for more information.



  • NCS0402 with AC/DC power adapter and dual-band GSM antenna.


  • Necoso GSM Application Suite, consists of:

  • GSM application, for communications over a GSM network. Supports GSM data, GPRS and SMS. Comes with an number of helper applications for web based configuration and diagnostics.

  • CLI application, enables remote control of G2S bridge using telnet and/or SMS.

  • Log application, for logging events.

  • DynDNS application, enables use of fixed domain names (e.g. for GPRS connections.

  • G2S application, bridges data between a serial interface and the GSM interface of the NCS0402.

    The G2S applications supports:

    • Serial communications: baudrates from 2400 to 57600 baud, 7 or 8 data bits, 1 or 2 stop bits, odd/even/no parity, no flow control or XON/XOFF flow control.

    • Optional modem emulation (V25) at serial interface side.

    • Optional SLIP or PPP as carrier protocol at serial interface side.

    • PPP as carrier protocol at GSM interface side (for GSM data connections)

    • Configurable TCP/UDP port. (for GPRS connections)

All software is pre-installed on flash disk of the NCS0402.


  • CD-ROM with installation manual, data sheets and application notes.


  • One year of free application updates when they become available.

Not included

  • SIM card - You must purchase a SIM card with the appropriate GSM services from a GSM provider yourself. Note that if remote device access is wanted via the public internet, then a SIM card is required that supports the GPRS service and is assigned a public IP address whenever it attaches to the GPRS network. Not all GSM providers offer this service for their SIM cards. Click here for more information.
  • Serial cable - the type of serial cable (RS232/RS485, cross/nul-modem, etc) and the length of the cable that is required for connection to the G2S bridge to you're device depends on the interface options available with your device.

Click here for latest datasheet. 

Click here to contact us for more information about the G2S bridge.


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Necoso, Het Kasteel 315, 7325 PE Apeldoorn, The Netherlands
Phone: +31 (0)55-3601410, fax +31 (0)84-7246122
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Last updated:07-jan-2013