Introduction

1.3Modem Connection Overview

The DCE (modem) operates in one of two states: command or online. In each state, both data and commands (including DCE responses) are transferred through the UART THR (Transmit Holding register) and the RBR (Receiver Buffer register).

The modem defaults to the command state. In the command state, the DTE (host) communicates to the modem through AT commands and S-registers. AT commands are character strings that help guide modem operation. S-registers are internal modem registers that the DTE can access. The S- registers contain modem status and configuration information. Many of the AT commands indirectly affect the contents of the S-registers. The AT command set and S-registers are divided into the following modes: Group 3 fax, data, V.44/V.42 bis/V.42/MNP, and voice. Note that supported AT commands are firmware revision-dependent (that is, not all commands are supported by all modem models or all firmware revisions).

All command lines sent to the modem, except for A/, must be preceded by an ‘AT’ (which stands for ‘attention’) and terminated by the contents of S-register S3 (typically a carriage return <CR>). The ‘AT’ prompts the modem to receive a command line from the DTE. A <CR> informs the modem that the entire command string has been transmitted and that the modem should start processing all the commands within the command line.

A command line may include one or more AT commands that may or may not be separated by a space. AT commands may be either upper- or lower-case characters, but all characters for a given command must use the same case. If there are multiple commands in a line, a semicolon (;) must be placed after each fax or voice command. The modem can be configured to send back (echo) to the DTE any data that the DTE sends to the modem (while in command state only). The last command may be repeated by typing A/ without using a carriage return. Each command line may include up to 80 characters and spaces.

Examples of AT command strings:

ATS1?<CR>

A/

AT &C1 &D2 +FCLASS=? <CR>

AT &C1 &D2 +FCLASS=?; S0=1 <CR>

The modem provides status information to the DTE in the form of response codes. These response codes can be expressed in text or numeric form. The supported response codes are provided in Table 4 on page 12.

Examples of modem responses:

+MCR: V90

+MRR: 28800

CONNECT 50666

In the online state, the DCE is off-hook and communicating with a remote modem. Any data sent from the DTE to the DCE is transmitted to the remote modem. Similarly, any data that the DCE receives from the remote modem is transmitted to the DTE.

Note: In the online state, the DCE does not ‘echo-back’ any of the data that the DTE sent to the DCE.

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536EX Chipset Developer’s Manual

Intel Confidential

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Intel 537EX manual Modem Connection Overview
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537EX specifications

The Intel 537EX is a powerful and innovative embedded processor designed for a range of applications, particularly in the fields of industrial automation, telecommunications, and transport management systems. This processor is a member of Intel's embedded product line, tailored specifically to meet the demands of systems that require high reliability and long lifecycle support.

One of the main features of the Intel 537EX is its multi-core architecture, which enables efficient parallel processing capabilities. This allows for the execution of multiple tasks simultaneously, significantly improving overall system performance. The processor also incorporates Intel’s advanced power management technology, which ensures that the device consumes energy efficiently, enhances thermal performance, and prolongs the lifespan of the system.

The Intel 537EX supports a range of connectivity options, including high-speed Ethernet and Serial ATA interfaces. This ensures that it can easily integrate into existing systems, seamlessly supporting applications that require robust data transfer capabilities. Additionally, the processor is equipped with multiple I/O ports, facilitating the connection of various peripherals and sensors, which is crucial in industrial applications.

One of the standout technologies within the Intel 537EX is its support for hardware virtualization. This feature allows for the creation of multiple virtual environments within a single physical structure, optimizing resource utilization and enhancing system flexibility. Additionally, Intel’s integrated security technologies provide a significant layer of protection against potential threats, ensuring that embedded systems remain secure.

Another characteristic of the Intel 537EX is its extensive software support, which includes compatibility with various operating systems and development environments. This versatility makes it an attractive choice for developers looking to build or upgrade their embedded systems. With access to Intel's comprehensive software tools, developers can quickly optimize applications to take full advantage of the processor's capabilities.

The Intel 537EX also boasts excellent thermal performance, allowing it to operate efficiently in harsh environments. This is crucial for embedded applications in industrial settings where temperature fluctuations are common. Overall, the Intel 537EX is engineered to deliver high-performance processing power, superior connectivity, and enhanced security, solidifying its position as a reliable choice for demanding embedded applications.
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