Intel 537EX manual AT Commands Overview, DTE-to-DCE Data Rates for Each Mode

Introduction

The modem recognizes AT commands from the DTE at any valid data rate from 300 bps to 115,200 bps (that is, the modem autobauds up to 115,200 bps); however, the DTE should use the data rate specified for each mode according to the transmitting direction—DTE-to-modem (Table 1) or modem-to-modem (Table 2). The V.90 and V.92 data rates are effective only in DCE-to-ISP connections.

Table 1. DTE-to-DCE Data Rates for Each Mode

Mode	Data Rate (bps)	Affected Data
Data (V.34)	2400–115,200
Data (V.90)	28,800–115,200	DTE-to-modem data rate
Data (V.92)	28,800–115,200
Fax	19,200
Voice	19,200–115,200	AT commands, playback and record modes
		(varies according to compression type)

Table 2. DCE-to-DCE Data Rates for Each Mode

Mode	Data Rate (bps)	Affected Data
Data (V.34)	2400–33,600
(transmit and receive)		DTE-to-modem data rate
Fax	300–14,400
Voice	19,200–115,200	AT commands, playback and record modes
		(varies according to compression type)

Table 3. DCE-to-ISP Data Rates for V.90 Mode

Mode	Data Rate (bps)	Affected Data
Data (V.90) transmit	4800–33,600
Data (V.90) receive	28,000–56,000	ISP-to-modem data rate
Data (V.92) transmit	24,000–48,000
Data (V.92) receive	28,000–56,000

Each command may have one or more parameters associated with it. If a parameter is not sent for a command requiring a numeric parameter, then the modem assumes a zero (‘0’) parameter (only if zero is a valid parameter for the command). For example, ATZ and ATZ0 commands perform identical functions (that is, the modem sees ‘ATZ’ and automatically uses the ‘0’ parameter during processing the command). Other commands do not use parameters.

1.4AT Commands Overview

The AT command set and S-registers are divided into four categories: data, Group 3 fax, voice, and V.42/MNP. Summaries of all commands are provided later on in this chapter.

536EX Chipset Developer’s Manual 11

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