The GSM-to-ethernet solutions are used when the communications reach for an existing device with an ethernet interface (TCP/IP) is it to be extended with a wireless dial-in or dial-out connection. For example for out-in-the-field installations, when no wired intranet or ethernet network is available. Or for situations where the end-user does not allow use of the local wired infra-structure or independence of local infra-structure is wanted. (e.g. for security or availability reasons)
Solution example 1: GSM-data-to-Ethernet bridge
Original configuration: The configuration consists of an existing OEM device that has an ethernet interface and PC that runs an OEM specific application that communicates with the OEM device locally over an intranet using the TCP/IP protocol.
Wanted: Remote access to the device is wanted using wireless GSM data technology.
An external PSTN modem is assumed in the figure above. But in fact this could have been any internal/external analog/digital modem with access to PSTN, ISDN or GSM network directly. For mobile users it could also have been the combination of a laptop and a mobile phone acting as a GSM modem as depicted below:
The end-to-end connection between the PC and the OEM device is a regular PPP connection carrying TCP/IP packets.
The NCS0402 emulates a dial-in PPP server and performs the GSM-data-to-ethernet bridging and IP network address translation. (NAT)
GSM-data-to-ethernet bridging has some disadvantages when compared to GPRS-data-to-ethernet bridging:
The GPRS-to-ethernet solution (see below) overcomes some of these problems and usually is a better, more cost-effective solution for those situations where large amounts of data are to be transferred or frequent or instant access is required.
In the solution above we assumed interactive communications with the device, initiated by the user on the PC. However, the same solution can also be used for non-interactive, automated, configurations. Or for communications that are initiated by the OEM device. For example for periodic uploading of device data to a central server over ethernet using FTP. (device dial-out)
Necoso has ready-to-use GSM-data-to-ethernet bridge solution available, click here for the specifications.
Solution example 2: GPRS-to-Ethernet bridge
Original configuration: The configuration consists of an existing OEM device that has an ethernet interface and PC that communicates with the OEM device locally over an intranet using the TCP/IP protocol.
Wanted: Remote access to the device is wanted using wireless GPRS technology. Optionally: access to the device via the public internet.
The NCS0402 performs the GPRS-to-ethernet bridging and network address translation. (NAT)
Advantages of GPRS-to-ethernet bridging when compared to GSM-data-to-ethernet bridging:
PC initiated communications
Usually intended for interactive communications with the device for control or maintenance purposes. (using web browser, FTP, telnet)
Direct access to the device using the public internet is only possible if your GSM provider assigns a public IP address to your SIM card. As for the Netherlands currently the following GSM providers offer this public IP address service:
Other GSM providers ‘hide’ their GPRS network behind a NAT server, which means the device will not be accessible from the public internet for PC initiated communications. PPTP tunneling or static routing using a dedicated APN might be an option in such situations. Contact us for more information if you are not sure about your GSM provider.
Device initiated communications
Usually intended for unattended, automated, data retrieval. The device logs on to a specific internet host and transfers data to the server. Using email, FTP, HTTP, telnet or custom high level protocols for data transfer. Log on by device is periodically (data acquisition) ,event driven (e.g. in case of alarm) or a combination of both.
Necoso has ready-to-use GPRS-to-ethernet bridge solution available, click here for the specifications.
Solution example 3: Email-to-SMS conversion
Original configuration: This configuration includes a network enabled device that uses e-mail over an intranet/internet to periodically report status/alarm information or acquired data to a central server.
Wanted: Communications with the same device in an outdoors environment where there is no ethernet network available. (e.g. in-the-field telemetric module for water management station, weather station)
The NCS0402 at the OEM device side intercepts the email messages transmitted by the device and translates them into SMS messages. The NCS0402 at the service side intercepts the SMS messages transmitted by the device and translates them into e-mail messages, which are delivered to the SMTP service in the central server.
Translation is in the other direction is also possible. In that case the NCS0402 translates incoming SMS messages into emails and emulates a POP3 mail server that enables the device to retrieve the incoming emails.
The NCS0402 at the server side can be omitted if the application on the central server supports a direct connection to the SMS Service Center of the GSM provider. In this case the SMS messages are retrieved directly from the GSM provider’s SMS server and translation into e-mail can be done at the central server. (see figure below)
This solution is intended for network enabled devices that periodically sent small status messages or alarms in form of emails over an ethernet network. But if no intranet/internet infra structure is available (e.g. outdoor location) the SMS facility is to be used as a replacement to get the message or alarm to the destination server or service personnel.
For devices that must send large amounts of data we recommend a GSM data or GPRS based solution.
Necoso, Het Kasteel 315, 7325 PE Apeldoorn, The Netherlands