MFJ MFJ-1270C, Системное руководство

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MFJ-1270C/1274C COMPUTER INTERFACING
Page 16
Frame Ground is provided for attachment to the chassis of the MFJ TNC and
the chassis of the attached device (computer or terminal). This pin is brought
out to a feedthrough on the MFJ TNC PC board near pin 1 of the serial
connector. It is not electrically connected anywhere else on the MFJ TNC
circuit board.
Transmit Data is an input line to the MFJ TNC on which the attached device
sends data.
Receive Data is an output line from the MFJ TNC on which the attached device
receives data.
Request To Send is an input line to the MFJ TNC which the attached device
requesting clearance to transmit.
Clear To Send is an output from the MFJ TNC signaling the attached device to
send or refrain from sending data to the MFJ TNC . This line is used for
hardware flow control.
Data Set Ready is an output from the MFJ TNC telling the attached device that
the MFJ TNC is operational.
Signal Ground is the common, or return, path for all signals between the MFJ
TNC and the attached device.
Data Carrier Detect is an output from the MFJ TNC . As normally configured,
DCD reflects the status of the CON LED: It is true when an AX.25 connection
exists between your MFJ TNC and another station; it is false when no
connection exists. This configuration is useful when the MFJ TNC is used with
a telephone style Bulletin Board system, since the AX.25 connection, analogous
to a modem signal on the telephone, indicates the presence of a user. Shorting
pin 1 and 2 of JMP1 on the MFJ TNC board will cause this output to always be
true.
Computer Baud Rate
Turn off the power to your computer and to your TNC. Connect the computer
and TNC with a properly configured serial cable. Set the DIP switch on the rear
panel of the TNC to the desired baud rate as shown in Table 2-4. The power
must be OFF when these switches are set.