Intermec CV30 Intermec Terminal Emulator (ITE) Programmer's Reference Manual - Page 51

Chapter 1 - About 3270 and 5250 Programming Asynchronous 5250 Prefixes Each asynchronous 5250 data stream command is preceded by a variable-length prefix. The first byte of the prefix contains the number of bytes in the prefix, not including the length byte. The length may be zero, which indicates an empty prefix. The second byte of the prefix (if the length is nonzero) must be either hex 40 or C0. • Hex 40 indicates that the data in the rest of the message is LU-LU (normal 5250 commands). • C0 indicates that the rest of the message is SS-LU data (an SS message). SS messages cause the computer to enter the SS message state, where Reset is the only allowable keystroke. The SS message is a one-line message displayed on the computer's status line until the Reset key is pressed. After hex 40 or C0, the 5250 prefix may contain one 5250 signal. A signal is a sequence of 5 bytes that tells the computer to perform a special operation. The following Signal command formats are supported. Hex Code Description C9 00 00 00 01 Signal operator. Turns on the Message Waiting annunciator and sounds the audible alarm. C9 00 00 00 05 Resets the Message Waiting annunciator A parameter error is posted when the message includes less data than indicated by the length byte. This causes a parameter error of "21." If the computer encounters data it does not understand, it ignores the rest of the prefix. System Messages and Parameter Errors The computer display reserves a line for status information, which can display system (nonlocal) information such as a message waiting from the host computer, help messages in response to the Help key, or the system request state of the computer. You can program the location of the status line through the Start of Header order. System codes can also appear on the status line. Parameter errors displayed when the stated condition occurs are listed below. Unless otherwise noted in the table, the computer Reset key restores the status line and returns to the keying mode in effect when the problem occurred. System Messages and Parameter Errors Code 0005 0006 0007 0008 0009 0010 0011 Description Attempt to enter data when not in a field. A key other than a data key or Enter pressed in the system request state. A mandatory entry field has not had data put into it. The field is alpha only, and an invalid key was pressed. The field is numeric only, and an invalid key was pressed. The field is signed numeric, and an invalid key was pressed. Data cannot be entered into the last byte of a signed numeric field. Intermec Terminal Emulator (ITE) Programmer's Reference Manual 39