Lucent Technologies 7400B manual Operating Modes, Line or data mode, Character Formats

DEFINITY Communications System	CHAPTER 3: FIRST TIME USERS
7400B Data Module
User’s Guide	Page 3-1

CHAPTER 3: FIRST TIME USERS

	This chapter provides some basics on 7400B Data Module operation,
	describes how to use a few AT commands that are essential for most data
	communications operations, and then outlines a typical on-line session.
	Note: The commands for the data module are referred to as AT
	commands because you must type the letters “AT” as the
	first characters on the line for most commands.
OPERATING MODES
	Except when the 7400B Data Module is in a test mode, it is always in
	one of two distinct operating states or modes: command mode and on-
	line or data mode.
	In command mode, the data module tries to interpret everything you
	type on your keyboard as a command. In on-line mode, the data module
	passes everything on as data.
	While in on-line mode, typing a specific character three times in quick
	succession (the factory-default escape sequence is 3 plus signs, or +++)
	causes the data module to go into command mode without disconnecting
	an active data call.
	The operating modes, the escape sequence, and several AT commands
	are explained further in Chapter 4, “Operation and Configuration.” All
	AT commands are described fully in Appendix A, “AT Commands.”
Character Formats	In this context, character format refers to the form a character may take
	locally, between the 7400B Data Module and your terminal device. The
	elements that make up character format are often referred to as
	communication parameters. Formats supported by the 7400B Data
	Module are shown in Table 3-1.
	Data Bits	Parity	Stop Bits
	7	even or odd	1
	7	mark or space	1
	8	none	1

TABLE 3-1 CHARACTER FORMATS