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Chapter 1 – Introduction

CDMA 1xEV-D0 AT Commands Reference Guide (Document S000482B) 8

The default settings are noted in the command tables. Note that these are the factory default settings and not the

default parameter value assumed if no parameter is specified. The factory defaults are also noted in a section at

the end of each operational mode reference.

Result Code – This is a numeric or text code that is returned after all commands (except resets). Only one result

code is returned for a command line regardless of the number of individual commands contained on the line.

Response – This term indicates a response from the modem that is issued prior to a result code. Reading

registers or issuing commands that report information will provide a response followed by a result code unless

the command generates an error.

For a discussion of how the modem frames these two elements, see “Framing”.

Responses and result codes from the modem, or host system software prompts, are shown in this font:

CONNECT 14400

Modem Basics

CDMA Basics

To help understand the call connection process in CDMA modems, a basic knowledge of the CDMA network

helps. Two primary services are available using a CDMA 1xEVDO modem:

• IS-95B, a circuit switched type of connection; and

• 1x/1xEVDO, a packet switched connection.

Traditional Wire Line

Before looking at the call setup process in CDMA, let's take a moment to review the traditional wire line

modem. A call is established by the local modem placing the call over the Public-Switched Telephone

Network (PSTN). The local and remote modems are connected and handshake the data protocol to use. The

local modem can monitor the call progress by picking up the dial tone, busy, ring, and answer from the PSTN

wire line connection.

CDMA IS-95B

Not being connected to the PSTN, the modem must first connect to the CDMA network. The CDMA service

provider connects the call to either the PSTN or (by using QNC) the Internet. This environment uses an

Interworking Function (IWF) to bridge the two systems.

CDMA IS-95B Call Connection Block Diagram

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