Operator's Guide

G-3

DATA BITS. Defines the number of data bits in each byte transmitted. A setting of 7 data bits is used to send ASCII characters 0 through 127. A setting of 8 data bits is required for sending graphics data and data byte values between characters 128 through 255.

DATA BYTE. A string of 7 or 8 bits that represents one character.

DATA BYTE ACTION MAP. Describes whether a data byte value between 0 and 255 is currently defined as a control code or a printable character.

DATA BYTE MAP. A group of five maps in printer memory that describe the action the printer is currently set to perform when it receives a data byte. A complete data byte map consists of the data byte action map, the control code map, the character source map, the character library map, and the character number map.

DECENDERS. That part of a character that falls below the character's baseline. Also, a term used to describe a subscript character.

DECIMAL. The numbering system that uses the numerals 0 to 9.

DEFAULT. A value or setting that is used if no alternate setting is specified. Default settings are in effect when the printer is turned on or reset.

DOWNLOAD. To send data from the computer to the printer.

DTR. Data Terminal Ready (DTR) is a hardware handshaking protocol in which a receiving device controls data flow by changing the voltage level on a signal wire.

ERASEABLE PROGRAMMABLE READ ONLY MEMORY (EPROM). A specific type of

ROM. The printer uses a 128K x 8 bit EPROM for storing the software that has been electronically programmed into this ROM device. A programmed EPROM is sometimes referred to as "firmware."

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Epson 4100 manual