53
If the communication specification and the valid signal line are omitted, their de-
faults are:
Peripheral Device
Communication
Conditions
Valid Signal Line
Terminal
4
3
Keyboard
4
3
Display
4
3
RS-232C device
4
3
Printer
4
3
Ports already open cannot be opened again. When the OPEN and CLOSE
statements are used, port 1 is assumed to be for a terminal and port 2 is as-
sumed to be for a printer. Port 2 cannot be selected for a terminal.
I/O statements specifying #<port> cannot be used to transfer data through a port
that has not been opened with the OPEN statement. To input/output data in the
case where the OPEN statement has not been executed, use the I/O statements
without the #<port> specification.
The following two tables illustrate peripheral device output levels during execu-
tion of the OPEN statement.
Device
When Opened
During Operation
RTS
DTR
RTS
DTR
TERM
LOW
HIGH
HIGH
No change
SCRN
LOW
LOW
HIGH
No change
KEYB
LOW
HIGH
HIGH
No change
COMU
LOW
HIGH
HIGH
No change
LPRT
LOW
LOW
HIGH
No change
Device
When Closed
RTS
DTR
1
LOW
HIGH
2
LOW
LOW
Note The default selection for the ports is as follows:
Port 1: Terminal device
Port 2: Printer
The following table presents the output control codes for the terminal, printer,
and COMU device.
SCRN TERM
Clears the screen buffer when code &H0C (CLR) is output.The column position is set to 0 (i.e., the
leftmost position) when code &H0A (LF), &H0D (CR), &H0B (HOME), or &H08 (BS) is output. The
cursor is moved as specified on the screen when code &H08 (BS), &H1C (->), or &H1D (<-) is
output. Codes &H00 to &H09 and &H0E to &H1B are ignored (no output) at Port 1 but are output at
Port 2.
When Closed: Nothing is executed.
LPRT
Set the column position to 0 (i.e., the leftmost position) when code &H0A, &H0D, &H0B, or &H0C is
output. Characters exceeding 80th character are output with code &H0A (LF) appended.
When Closed: If characters (80 characters or less) remain in the buffer, they are output along with
&H0A (LF).
COMU
If characters are input to the buffer, they are output.
When Closed: If characters remain in the buffer, they are output.
Commands, Statements, and Functions
Summary of Contents for C500-ASC04
Page 1: ...C500 ASC04 ASCII Unit Operation Manual Revised February 2001 ...
Page 5: ...iv ...
Page 7: ...vi ...