Com Connector; Hardware Description; Control Operation - Kenwood TS-2000 Instruction Manual

COM CONNECTOR

HARDWARE DESCRIPTION

This transceiver uses a full-duplex, asynchronous,
serial interface for communicating through the male
9-PIN RS-232C COM connector. Each data is
constructed with 1 start bit, 8 data bits, and 1 stop bit
(4800 bps must be configured as 2 stop bits). No
parity is used. The pinout and the pin functions of the
COM connector are shown below:
9
5
Rear panel view
COM Pin Name
COM
(Ref.: Computer)
Pin No.
1 NC
2 RXD
3 TXD
4 NC
GND
5
NC
6
7 RTS
8 CTS
9 NC
RXD: Transmit data is serial data transferred from
the transceiver to the computer.
TXD: Receive data is serial data transferred from
the computer to the transceiver.
GND: Signal ground pin
RTS: This signal is applied to the transceiver. It is
used to inhibit transmit data from the transceiver
when the computer is not ready to receive data.
Transmit data is inhibited when the level is low.
CTS: This signal is applied from the transceiver. It
is used to inhibit transmit data from the computer
when the transceiver is not ready to receive data.
Transmit data is stopped when the level is low.
COM
8 7 6
4 3 2 1
Function
(Ref.: Transceiver)
—
Transmit data
Output
Receive data
Input
—
Signal ground
—
Receive enable
Input
Transmit enable
Output
—

CONTROL OPERATION

Most computers handle data in the form of "bits" and
"bytes". A bit is the smallest piece of information that
a computer can handle. A byte is composed of eight
bits. This is the most convenient form for most
computer data. This data may be sent in the form of
either serial or parallel data strings. The parallel
method is faster but more complicated, while the
serial method is slower and requires less complicated
equipment. The serial form is, therefore, a less
expensive alternative.
Serial data transmission uses time-division methods
over a single line. Using a single line also offers the
advantage of reducing the number of errors due to
line noise.
Only 3 lines are required theoretically for control of
the transceiver via the computer:
• Transmit data
• Receive data
I/O
• Ground
—
From a practical standpoint, it is also necessary to
incorporate some means of controlling when this data
transfer will occur. The computer and transceiver
cannot be allowed to send data at the same time!
The required control is achieved by using the RTS
—
and CTS lines.
For example, the transceiver is placed into the
—
transmit mode whenever the character string "TX;" is
sent from the computer. The character string "TX;" is
called a computer control command. It tells the
transceiver what to do. There are numerous
commands available for control of the transceiver.
—
These commands may be incorporated into a
computer program written in any high level language.
Programming methods vary from computer to
computer; therefore, refer to the instruction manuals
provided with the terminal program and computer.
21 APPENDIX
113