Standalone Modems

Standalone modems can be used to replace a wired dial up modem, but, without application changes, the system will operate in circuit switched data mode i.e. when data is to be transmitted, the modem will dial a phone number, expecting to communicate with another dial up modem.

A Serial Port replacement modem can offer a more advanced option for applications that use an RS232 or RS485 connection for communication with a remote host. When the modem detects there is serial data to be transmitted, a GPRS connection is used to transfer the data across the cellular network, the APN and the internet. Often, serial port replacement modems require a Fixed IP address, or virtual private network for robust operation.