Hal Communications CWR6850, Instruction Manual

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CHAPTER 4 PAGE 34
With a half duplex connection, all transmitted text from the CWR6850 may be seen on the screen
before and after it has been transmitted. All of the features of the CWR6850 may be used with half
duplex. However, the CWR6850 may only receive or transmit one at a time.
When full duplex is chosen, the CWR6850 can receive and transmit text simultaneously. However,
transmitted text will no longer be displayed in the receive section of the screen; it will, however,
appear in the transmit screen area as usual. Typical full duplex connections with a computer usu-
ally include a computer-generated "echo" back to the receive display or printer, showing the char-
acters as received and interpreted by the computer; transmission errors are therefore soon no-
ticed. The complete ASCII and Baudot character sets may be transmitted in FDX mode.
When using full duplex, use the AF IN - TAPE connector for received data; either the AFSK OUT -
TX or AFSK OUT - TAPE connector may be used for transmitted tones. The FSK TTL - IN and OUT
connectors may be used if the FSK DEMOD switch is set to EXT.
The "CTRL-E" echo command allows some interesting variations of full duplex. When the RX-TAPE
switch is set to TAPE and "CTRL-E" is used, received data is loaded into the transmit buffer and
you may then retransmit this received data. If the switch is set to RX position and "CTRL-E" is
used, text typed on the keyboard is entered into the transmit buffer, transmitted, and reloaded
back into the transmit buffer, forming a continuous loop.
4.8 The KOS Feature
The KOS (Keyboard Operated Switch) feature of the CWR6850 allows automatic control of the
transmit-receive circuits of the station in much the same manner as the SSB VOX circuit. Select the
KOS feature by setting the SEND-AUTO-RECEIVE switch to AUTO (center position). When you have
pretyped your text and are ready to start transmitting, type "CTRL-A". The transmitter will turn on
and, after a short delay, transmit the typed text. After all of the text has been transmitted, and
after another short delay, the transmitter will turn off. If you type any more text, the transmitter
will turn on again and that text will be transmitted. To pretype without further transmitting, type
"CTRL-A" again. The "A" on the status line of the screen shows if the automatic KOS feature is ac-
tive.
The on-off KOS control of the transmitter may be controlled manually with the "CTRL-X" command
(shows "X" on status line when active). The "CTRL-X" command turns the transmitter on for as
long as the "X" is shown on the status line; you must type another "CTRL-X" to turn off the trans-
mitter, whether there is text to be transmitted or not. More details regarding the "CTRL-A" and
"CTRL-X" commands are given in section 4.2.
The KOS switch transistor is NPN and will therefore key only transmitters with a positive voltage tx-
rx control line (push-to-talk line, usually). If your transmitter has a negative voltage control line
(the Drake M is an example), it will be necessary to use a relay or additional transistor switch be-
tween the CWR6850 KOS output and the transmitter. This variation is discussed in Section 5.1.
The SEND-AUTO-RECEIVE switch parallels the KOS (SW-OUT REMOTE) jack when it is in SEND po-
sition, manually turning on the transmitter.