USR® Courier® M2M Modemulator™ Expansion Card

FAQs

What is a “Modemulator”?

USR's exclusive “Modemulator” is a cellular device that serves as a drop-in replacement of serial dial-up modems. The Modemulator emulates a dial-up modem, which extends the life of application software and hardware while providing the benefits of cellular connectivity.

The Modemulator is also unique in that it can maintain support of peer-to-peer dial-up connections as well as cellular connections.

Why can't I use any cellular modem as a drop-in dial-up modem replacement?

Most cellular networks use a different type of technology that isn't compatible with dial-up analog systems. Our Whitepaper explains in detail the how's and why's but the high level answer is that most cellular data networks are packet based, rely on IP addresses, and are client/server whereas dial-up systems are peer-to-peer direct connection and rely on phone numbers which normally cannot communicate without additional hardware and/or software that could complicate how a solution works.

Learn more with the Cellular to Cellular Data Communications White Paper

Why Emulate an Analog Modem & the PSTN?

Legacy M2M application software that uses an analog modem for communications will send commands to the analog modem that set-up the modem and initiate or answer calls. Such software is generally not able to set-up and initiate or answer calls using a cellular data modem or gateway because cellular modem commands, cellular gateway GUI, and the cellular network are fundamentally different than the analog modem commands and phone network.

USR Modemulator technology allows a legacy M2M system to be conveniently converted to cellular without upgrading or replacing application software. The Modemulator accepts and responds to the most common analog modem commands, and sends result codes that mimic a PSTN connection to the application software, which enables drop-in compatibility with the legacy application software.

How much can I expect to save by replacing analog modems with Modemulators?

The cost of analog phone lines is on average $50 per month per line. Cellular services when pooled can provide even greater cost savings with small data packages and low data volumes. The cost savings increase as the volume goes up, whereas the dial-up monthly expenses are consistent but pricey.

Can I replace leased line analog modems with Modemulators?

With firmware release 1.0.02, leased line dial-up modems can be replaced and provide even greater cost savings per month.

Can I use the SIM from my phone for Modemulator?

Generally no. The SIM from your phone is not provisioned for peer-to-peer data connectivity, which Modemulators require in order to emulate the analog PSTN and dial-up modems. However, depending on how your SIM is provisioned, it may allow connectivity to the Internet, and Modemulator can use this type of connectivity when operating in single-ended mode to originate a connection to the IP address of a TCP/IP server.

Can I connect to the IP address reported by the USR3520?

When the cellular service is provided by a Mobile Network Operator (MNO), the IP address reported by the USR3520 GUI or I7 screen may be public and routable. Normally this IP address provided by the MNO will be dynamic so it will change periodically, and the MNO may block access to this IP address with a firewall.

When the cellular service is provided by a Mobile Virtual Network Operator (MVNO), the IP address reported by the USR3520 GUI or I7 screen is not public and routable. The reported IP address is used only by the MVNO to contact the cellular network. The MVNO will translate the IP address using Network Address Translation (NAT) and provide you with a different routable IP address. The USR3520 cannot report that IP address. The MVNO will control whether your IP address is private or public, and static or dynamic.

How does the Modemulator work?

In Modemulator (modem + emulator) mode, the Modemulator presents to a User (or to legacy application software) a command-line interface (CLI) that mimics the AT commands and responses of analog modems, but connects to another Modemulator (or to an IP server) over a cellular data network instead of the public switched telephone network (PSTN). This allows the easy conversion of a legacy M2M system that was based on analog modems connecting over the PSTN to a more modern M2M system connecting over ubiquitous cellular data networks, without upgrading legacy application software that expects an analog modem, or without installing new middleware onto the application computers.

To facilitate the gradual conversion of legacy systems to cellular, the Modemulator can also initiate and answer connections over the PSTN to sites with analog modems by automatically diverting commands to an analog modem attached to its MODEM serial port. This provides the User a unified interface and protocol for connecting with both cellular and analog sites.

Learn more with the Cellular to Cellular Data Communications White Paper