Kantronics KAM, Руководство пользователя

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Chapter 6 - System Operation and Control
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when they access the disk. The program should always send a
STOp
character before a disk ac-
cess in this case. If you send a
STOp
(
STARt
) character to the KAM when it is already stopped
(started) the character will be treated as data. If you have enabled echoes, and the
STOp
or
STARt
character is echoed, this may have undesired consequences {CTRL-S will lock some keyboards). If
the
STOp and STARt characters are the same character, this character will toggle the output, turn-
ing it OFF if it is ON, and ON if it is OFF.
If you disable XON and XOff by setting them to zero, the KAM will automatically use RTS/CTS
flow control to stop input from the terminal.
If you are using a terminal or terminal-emulating program , you may want to set XON and XOff
to something you can respond to, such as CTRL-G or a printing character that you don't use.
HARDWARE FLOW CONTROL
This method of flow control is preferred since it usually does not depend on the structure of a
particular program. However, most commercial terminal programs don't use it since it is not stand-
ard RS-232 modem protocol.
RS-232 defines 20 signal lines on the 25-pin connector. The Kantronics KAM, like most other
devices using RS-232, implements only a subset of these signal lines.
RTS/CTS HANDSHAKING
The RTS/CTS lines are used for hardware "handshaking" to control the flow of data between
the terminal and KAM.
The KAM implements this hardware protocol with the attached terminal via the request to
send/clear to send pair for transferring data between the KAM and the terminal. The KAM will as-
sert CTS when it is ready to accept data from the terminal, and negate this line when it is not
ready to accept data. Thus, if you find the KAM won't send data to your terminal, one of the first
items to check is to verify that the RTS line at pin 4 of the RS-232 port is functional. If the terminal
does not implement the RTS/CTS protocol, the RTS/CTS lines should remain unconnected.
Many simple serial I/O ports do not implement RTS/CTS handshaking. If these pins are not
connected at the KAM end, they will be pulled up by resistors. However, a non-standard serial con-
nector may use some pins for other purposes, such as supplying power to a peripheral device. So -
BE SURE THAT YOUR SYSTEM EITHER IMPLEMENTS THESE LINES OR HAS NO CONNECTIONS TO
THESE PINS OF THE RS-232 PORT.
Note that reference to RS-232 compatibility or the presence of the DB-25 type connector does
not guarantee that you have a full RS-232 serial port!
Should your computer not be able to communicate with the KAM with a 3 wire interconnect,
you may need to place some "jumpers" on your computer's RS-232 port. As a starting point we
suggest the following:
1. Jumper RTS to CTS
2. Jumper DTR, DSR and DCD
Many times this will cause the proper "high" and/or "low" conditions to appear on those pins of
the RS-232 port.
OBTAINING MARK & SPACE OUTPUTS FOR SCOPE MONITORING
The schematic diagram of the KAM indicates that Mark and Space outputs are available on pins
11 and 18 of J4. Provisions have been made for obtaining these outputs AFTER installing jumpers
between the points provided on the PC board. This is accomplished by locating the four holes in
the board marked MA and SP and adding wire jumpers between them. One pair of holes marked