MagTek MINI MICR RS232 - Manual (Page 19)

Section 4. Commands
11
SWB PARAMETERS
The SWB functions are listed in Table 4-2 and described below.
Control Characters and MICR Data
Control Characters may be added to the MICR data message. The characters are always
in the following locations:
<STX> <ESC> data <ETX> <CR> <LF>
The control characters, descriptions, and hex values are shown in Table 4-3.
Table 4-3. Control Characters
CONTROL
CHARACTER DESCRIPTION HEX VALUE
<STX> Start of Text 02
<ESC> Escape 1B
<ETX> End of Text 03
<CR> Carriage Return 0D
<LF> Line Feed 0A
For example, if <STX> and <CR> are set to YES, the message from the MICR Reader
will look like this:
MICR Data: <STX>data<CR>
Control Characters and Card Data
The control characters are also available for card data but they are applied to each track
individually. For example, if the <STX> and <ETX> options are set to YES, the card
data message is transmitted as follows:
Card Data: <STX>[TK1 data]<ETX><STX>[TK2 data]<ETX><STX>[TK3
data]<ETX>
Communication Modes
The selection of comm modes is a quick way of selecting multiple Control Characters.
For instance, to send a carriage return/line feed pair after the data, you can specify Comm
Mode 3.
Comm Mode 7, also known as Packet Mode, calculates an LRC (Longitudinal
Redundancy Check), and appends it to the data message. Also, if a <NAK> (hex 15)
character is received in this mode, the MICR Reader will resend the last message.