Hal Communications ST-6000, Инструкция по эксплуатации

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5-6
to switch external and separate loop circuits from Loop 1 or can be used in any application requir-
ing a switch-to-ground on mark type of control.
5.2.8 RS-232/MIL-188 Interfaces (Figure 5.11)
The ST-6000 also includes interface circuits to allow interconnection to devices requiring EI-
THER EIA-RS-232C or MIL-STD-188C data signal levels. Input data from either RS-232 sources (pin
4 of J5, the RS-232/MIL-188 connector) or MIL-188 sources (pin 6 of J5) are combined with a Key-
board data in signal (pin 5 of J3, pin 3 of J6 or pin 3 of J8) to produce the CMOS-Compatible Local
Data Output signal (pin 14 or J3). This Local Data Output signal can then be used to drive the tone
keyer or other devices. This signal also drives the KOS circuit for automatic control of transmit-re-
ceive functions of the station.
The Keyboard Data In signal can originate from the previously discussed Loop Sense signal
(standard AUXILIARY plug jumper), separate keyboard contacts or switching transistor that
switches to ground, or other loop-isolated data generation devices. Because of the various ways in
which this input can be used, parallel connections are provided on the AUXILIARY connector (J3,
pin 5), the KOS connector (J6, pin 3) and the Loop 1 & 2 connector (J8, pin 3).
Output signals compatible with RS-232 (pin 1 of J5) and MIL-188 (pin 3 of J5) devices are gen-
erated in the two sections of integrated circuit I9, a type 5558 dual operational amplifier. The am-
plifiers are driven by the signal called "Interface Drive" (pin 4 of J3, the AUXILIARY connector).
Thus, the interfaces can be driven from any CMOS-compatible data source within or external to
the ST-6000. The standard AUXILIARY jumper plug connects the Loop Sense output signal to the
Interface Drive input so that all Loop 1 data is available with both RS-232 or MIL-188 compatible
outputs. As suggested in section 3, these outputs can also be used to drive diode FSK circuits or
devices such as the HAL RVD-1002 or RVD-1005 Visual Display Units ("Voltage" or "EIA" inputs).
5.2.9 KOS Circuit (Figure 5.12)
The KOS (Keyboard Operated Switch) circuit of the ST-6000 allows automatic control of the
transmit-receive functions of a radio station or can be used for other control functions. The KOS
circuit senses the data from the Local Data signal output and the CW-ID hand key. Recall from the
above discussion that the Local Data output signal only reflects data to be transmitted (from the
keyboard, RS-232 input, or MIL-188 input). Therefore, ONLY transmit data is allowed to trigger the
KOS circuit. The KOS circuit will switch to transmit mode IF a spacing condition of 5 ms or more is
sensed from the Local Data signal or IF the CW-ID key is closed. Thus, the transmitter will be acti-
vated by the KOS if any key on the keyboard is depressed (KOS triggered by the start pulse) or if
the CW-ID key is used. The KOS will return to receive mode under three conditions; if the Local
Data remains in mark condition for more than 1 to 10 seconds (user adjustable), or 1 second after
completion of the CW-ID operation. Therefore, the station reverts to receive condition if the tele-
printer break key is used ("fast-break") if typing is stopped for a preset length of time (1 to 10 sec-
onds of mark) or upon completion of the CW-ID sequence. Adjustment of the mark time delay is
discussed in section 4.9. Notice that, when the KOS is in transmit mode, the post-autostart output
data line is held in mark condition and the power to the MOTOR receptacle is turned on.
5.3 Front Panel Indicators
The operation of the front panel indicators (see Table 4.2) can now be explained in terms of the
control circuitry of the ST-6000. The MARK, SPACE, and AUTO indicators are shown in Figure 5.9.
The MARK indicator is driven directly from the output of the slicer stage. Thus, it ALWAYS indicates