Placing and Receiving Calls 2-15

Placing and Receiving Calls

This section illustrates how to place and receive a variety of calls with your 3Com Impact digital modem. The digital modem uses AT commands and S registers for call management. See Appendix A, “AT Command Set Overview,” for instructions on use of the AT command set, and Appendix B, “AT Commands, Registers, and Result Codes,” for a tabular summary of the AT command lines.

Placing ISDN Data Calls

When you need to place a call from your PC or Macintosh, the 3Com Impact digital modem recognizes the AT command ATD to dial a digital ISDN data call. Depending on the setting of register S60, 56 Kbps (default) or 64 Kbps

B channel transmission speeds are used. Correct examples of outgoing circuit-switched digital modem commands with dial strings are:

AT D 1 908 555 7891

ATD19085555555

Multilink PPP Calls With Dynamic Bandwidth Allocation

The 3Com Impact digital modem supports Multilink PPP, which allows the two B channels to be virtually linked, thereby allowing a maximum digital connection of 128 Kbps. Note that both your service and the one that you are dialing into must support Multilink PPP, or the virtual linking will not occur. Multilink PPP is enabled by default.

Multilink configuration is facilitated through registers S80, S81, S82, and S83. Additionally, dynamic bandwidth allocation (DBA) in multilink mode is configured in register S70. Register S80 enables (the default) or disables Multilink PPP operation.

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3Com DIGITAL MODEM manual Placing and Receiving Calls, Placing Isdn Data Calls

DIGITAL MODEM specifications

The 3Com Digital Modem represents a significant advancement in communication technology, designed to enhance data transmission over telephone lines. This modem is a part of a lineage of 3Com products that focus on delivering robust networking solutions, tailored for both personal and professional use.

One of the main features of the 3Com Digital Modem is its high-speed data transfer capabilities. With speeds reaching up to 56 Kbps, it allows users to send and receive large amounts of data quickly, which is essential for applications that require efficient data exchange. This speed ensures smoother internet browsing, quicker downloads, and more reliable connections for applications such as video conferencing and online gaming.

The modem is equipped with advanced error correction technologies, including V.42 and V.42bis protocols. These protocols help to maintain data integrity by detecting and correcting errors during transmission. This results in a more reliable connection, reducing the likelihood of dropped calls or corrupted data transfers, which can be particularly frustrating for users engaged in critical business communications.

Another notable characteristic of the 3Com Digital Modem is its compatibility with various operating systems, making it versatile for different users. It supports Windows, Mac, and various other platforms, ensuring that it can be integrated seamlessly into existing systems without the need for extensive configuration. This plug-and-play capability simplifies installation for users, allowing them to get connected quickly and efficiently.

The modem also incorporates an innovative design that facilitates improved heat dissipation, ensuring optimal performance during prolonged use. Its compact form factor makes it suitable for both home and office environments, allowing for easy setup without consuming excessive desk space.

In addition to these features, the 3Com Digital Modem boasts strong security protocols, ensuring that users' data is protected against unauthorized access while being transmitted. This is particularly important in today’s digital landscape, where data breaches and cyber threats are prevalent.

Overall, the 3Com Digital Modem combines speed, reliability, and security, making it a valuable asset for anyone looking to enhance their connectivity experience. Its robust feature set and user-friendly design cater to a broad audience, from casual users to business professionals, reflecting the evolution of modem technology in a digital-first world.