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An example of a prefix is the STX (Start of Transmission) code. IAPrefix = None*# IBPrefix = STX ICPrefix = SOH Suffix A suffix is a subset of the Postamble. Like the prefix, it is normally assigned a specific ASCII code. Examples of suffixes are CR (Carriage Return) and LF (Line Feed). MASuffix = None # MBSuffix = ETX MCSuffix = CR MDSuffix = LF MESuffix = HT MFSuffix = CR and LF * Users also have the ability to select any ASCII character for use as a suffix. Scan the MJ label, then scan two labels from the Hexadecimal Conversion Table representing the character needed for the suffix. MJ Select Programmable Suffix Character Certain specialized applications require a two character suffix of ETB NUL. Scanning MI provides this. MISelect Suffix = ETB NUL Terminal ID Terminal ID characters are used to identify individual scanners when more than one scanner is interfaced with the host system. Options available are none (DISABLED) or digits 01 through 99. JAID Character = Disabled*# NOTE If you scan the label below, you must also scan two of the digits from the Digit Selection page. JBID Character = XX Code Identifier A code identifier may optionally be transmitted with the message. This option is provided so a host computer can identify the type of bar code scanned, as well as the encoded information. Scan Option FA to disable the code identifier. FADisable Code ID # * Scan Option FB to enable the code identifier. FBEnable Code ID The table below shows the default code-identifier character assignments. These can be changed using the procedure found in the Symbology Identifier Section. Table 4. Code Identifier Characters SYMBOLOGY CODE IDENTIFIER Code 39 a Code Interleaved 2 of 5 b Code Standard 2 of 5 c UPC/EAN/JAN d Code 128 f Codabar h Preamble or Postamble Selection Preambles and Postambles are composed of up to four ASCII characters. Each ASCII character is encoded as two hexadecimal numbers. Use the Hexadecimal Conversion Table in Appendix A to look up the hexadecimal equivalent. NOTE If you select a Preamble or a Postamble you must scan four ASCII characters, even if the Preamble or Postamble is less than four characters in length. This is done by scanning in null (NUL) characters for the additional characters. For example, if your Preamble is “AB” (in ASCII code), scan A, then B, then two null characters, or 4,1, 4,2 0,0 0,0 hexadecimal. Preamble A Preamble is a string of characters that prefixes a message that is transmitted to the host. The sequence and number of characters in a Preamble is determined by the type of host system. Although not all systems require a Preamble, those which do will only receive messages with the correct Preamble. The maximum preamble length is four characters. KAPreamble = None*# KBEnter Preamble IMPORTANT Scan Enter Preamble to enter a Preamble, then refer to the Hexadecimal Table in Appendix A. Postamble A Postamble is similar to a Preamble, except that it appended to the message which is transmitted to the host. Its maximum length is also four characters. LAPostamble = None*# LBEnter Postamble IMPORTANT Scan Enter Postamble to enter a Postamble, then refer to the Hexadecimal Table in Appendix A. Serial Commands General Serial Command Format Serial Commands are only accepted by the PSC scanner when in serial communications mode. Serial commands take the form: STX ESC LT1 LT2 ETX (Note: STX = ^B; ETX = ^C) STX, ESC, and ETX are ASCII codes whose values are 02H, 1BH, and 03H, respectively. LT1 and LT2 are uppercase ASCII letters (commercial A and @ are the same as those printed in earlier sections of this manual under their corresponding menu bar code labels). The ESC code that follows the STX code identifies this as a command. Some commands require parameters such as minimum and maximum code lengths, and strings of hexadecimal characters. When parameters are required by the command, they immediately follow LT2. There are never spaces within serial commands. ACK/NAK The scanner provides ACK/NAK protocol during serial programming in order to provide feedback to the host computer which is programming the scanner. ACK/NAK protocol provides two vital functions. First, it provides the host with positive acknowledgment that its commands are being accepted and acted upon. Second, and perhaps more important, it ensures that the host will not issue commands to the scanner more quickly than the scanner can process them. For example, every time the scanner receives a correct command, it modifies its internal EEPROM, a function that takes about one second. At 9600 baud, the host can easily issue commands to the scanner faster than they can be processed. If after issuing each command the host waits to receive an ACK or NAK code before issuing the next command, the scanner cannot be overrun. If XON/XOFF or CTS/RTS Protocol is being used, the scanner cannot be overrun by programming commands. However, the host is not provided with feedback as to the outcome of its comm...

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