Acom 700S User Manual page 24

For details and recommendations on the grounding and RF counterpoise system concerning the
electromagnetic compatibility see also Section
.
problems
b) KEY IN connector
This is the amplifier's input for receive/transmit control from the transceiver.
The transceiver switches the amplifier from receive mode into transmit mode (RX/TX) by grounding of the
KEY IN input.
Run a shielded cable from the "ground on transmit" connector or terminal on your transceiver to the
amplifier rear panel KEY IN connector (see
connector uses a standard RCA phono plug.
The switching voltage presented from amplifier KEY IN connector to the transceiver
"ground on transmit" output does not exceed 12 V (positive to the ground). The closed-
circuit is below 6 mA (see Section
Your amplifier will NOT WORK if KEY IN input is not connected properly.
Transceiver producers give different names to this output and they are for instance
TX-GND, SEND, T/R-LINE, PTT, etc. Some transceivers require that "ground on transmit"
is implemented via a software command, or by changing the setting of a switch on the
rear panel, or interior of the transceiver. Check your transceiver's manual.
c) KEY OUT connector
This is the amplifier's transmit-enabling control output from amplifier to the transceiver.
The KEY OUT connector provides an extra control signal from the amplifier to the transceiver. It can be
used for improving the receive/transmit (RX/TX) switching safety.
KEY OUT is a low-power open-drain output, make sure that the signal voltage coming
from the respective transceiver connection does not exceed 50 VDC (open circuit) and
the closed-circuit current is below 20 mA.
If your transceiver has a suitable input that disables transmission unless grounded externally, we
recommend that you connect it with a shielded cable terminated in a Phono (RCA) connector to the
KEY OUT connector (see
Page 24 of 92 | S e c t i o n INSTALLATION
Figure 2-4 | Rear panel - Connections
8.2.a) Receive / transmit control
Figure 2-4 | Rear panel - Connections
User's Manual | ACOM 700S | 1.8-54 MHz Linear Amplifier
3.6.f) Elimination of electromagnetic compatibility (EMC)
NOTICE
, Pos. (c)) of the amplifier.
, Pos. (b)). The KEY IN
).
April 2024