Apr/2006 - Honeywell KHF 1050 System Installation Manual

5.E.(4) EXTERNAL MODEM AUDIO Output from Receiver/Exciter
(J10531-42 & 62)
The receiver/exciter provides an unsquelched, EXTERNAL MODEM AUDIO
Output that is a balanced output for use by an external modem. This output is
factory adjusted to provide 0.775 VRMS +/-5% (1 mW) into a 600 ohm load, and
is active when the receiver/exciter is receiving in any modulation mode. If
necessary, this output can be adjusted by a service adjustment located on the
top of the Receiver Exciter. See
adjustment. Accessing this adjustment requires removing the dust cover
5.E.(5) External Modem Audio Input High/Low- (J10531-42/62)
EXT MODEM AUD INPUP H/L
The audio signal level is typically 0.775 VRMS across 600 ohms.
The KRX 1053 Receiver/Exciter presents a balanced, floating 600 ohm load to
this signal.
This input does not present direct-current bias to the signal source.
There is no audio clipping or compression associated with this input at normal
operating levels.
This input is factory adjusted so that 1 KHz modem input signal of 0.775 VRMS
yields nominal Data USB output power from the KRX 1053 Receiver/Exciter.
5.F Discrete Inputs and Outputs
5.F.(1) Key Event - (J10531-13) KEY EVENT
The KRX 1053 Receiver/Exciter asserts (grounds) the KEY EVENT discrete
output when the transmitter is activated by any activation method.
This output may be used by external equipment, such as a flight recorder, to
sense when the HF system is transmitting. Maximum sink current is 100 mA.
5.F.(2) Maintenance Test- (J10531-78) MAINT TEST
When the MAINTENANCE TEST discrete input is asserted (grounded), the
KRX 1053 Receiver/Exciter RS-232 Maintenance port accepts test commands
from the KHF 1050 Maintenance Program (P/N 222-31044-0000).
This input is continuously read.
Revison 2
N
KHF 1050 SYSTEM INSTALLATION MANUAL
"10.B. Field Alignment"
23-10-09
for the location of this
Page 2037

Apr/2006