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Peripheral Devices
The optional parameter tt<char >P" is the decimal equivalent of an ASCII character which can
be used to turn off Record mode. It should be the first character in a record; the default
character is tto". If tt<char>p" is omitted or if tto p " is specified, no character will turn off
Record mode. Termination can only occur by pressing
RECORD MODE
or initiating a soft or hard
reset. The reset can be initiated either from the keyboard or from the program.
The termination character selected in the escape code is valid only for the current activation
of Record mode. When Record mode is ended, the termination character returns to the default
character
C
t
0").
If the escape sequence is received from the computer, the terminal returns an tts" or ttF"
character to the program to indicate ttsuccessful" or ttfailed", status execution of the escape
sequence. This status check is discussed later in this section.
When the status character is sent depends on whether or not the DCI/DC2 handshake is
enabled. (Refer to Sections 3 and 9 for information on handshake types.) If the DCI/DC2
handshake is disabled, the character (always an tts") is sent immediately after the terminal
receives the escape sequence; otherwise, it (an tts" or ttF") is sent after Record mode is turned
off and a DCI is received from the computer.
A 256-character buffer is used to hold each record prior to sending it to the ttto" device(s). If
the record exceeds 256 characters, the terminals handshake holds off any further transmis-
sion from the computer until the buffer contents are sent to the ttto" device(s). Records shorter
than 256 characters are indicated by an LF (line feed) character. In this case also, the termi-
nals handshake holds off further transmission from the computer until the buffer is cleared.
If Record mode is turned off with a partially-filled buffer, the contents are sent to the ttto"
device(s).
If the first character in the buffer is the termination character, Record mode is terminated
and the termination character is not sent to the ttto" device(s).
DATA LOGGING MODES
The terminal includes a mechanism called ttdata logging" whereby data can be automatically
routed to the integral printer and/or an external printer. There are two types of data logging:
top and bottom.
Log Top Mode
When the display is filled and another line of data is entered through the keyboard or
received over a datacomm line, the top line in the display is purged to make room for the new
line. With top logging, each line that is purged from the top of the display is printed. Thus,
while the line is ttlost" from display memory, it is maintained in hard copy form. Figure 6-5
illustrates top logging.
6-9
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