Hal Communications ST-6000, Инструкция по эксплуатации

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The general block diagram of the ST-6000 and a listing of the rear panel pin connections is
shown in Figure 5.1. The connections made by the AUXILIARY jumper plug furnished are shown
by the dotted lines. This figure, as well as the discussions of section 5, Theory of Operation,
should be carefully studied before alternate connections to the ST-6000 are attempted. The follow-
ing sub-sections discuss some of the possible alternate connections that may be desirable.
3.3.1 Use of External Loop Supplies and Multiple Loop Circuits
As can be seen from Figure 5.1, the ST-6000 contains two loop switching transistors, Q1 (Main
keyer stage) and Q2 (Auxiliary keyer stage). Both of these transistors switch a positive voltage to
ground on Mark condition and are both driven from a common data source, The internal, 175 Volt,
60 mA (nominal) loop power supply is connected through the LOOP 3 jumper plug to a pin on the
LOOP 1 & 2 plug, The standard connection to the loop is between pins 1 and 4 of this connector,
thus using the internal loop supply, LOOP 3 jumper, and Q1, the main keyer stage. However, an
external loop supply could be used simply be connecting the loop circuit between pins 4 (the col-
lector and 5 (ground)) of the LOOP 1 & 2 connector. When using this connection, be sure that the
positive loop voltage is applied to pin 4, the collector of Q1. Similarly, a SEPARATE loop supply and
equipment could be connected to use the auxiliary keyer stage, Q2, by connecting between pins 2
(positive) and 5. When there are a large number of mechanical machines to be drive, it is some-
times desirable to split them into multiple loops to keep the total loop inductance (and therefore
distortion) to a minimum. These alternate loop connections are diagramed in Figure 3.5. The keyer
transistors themselves, particularly the Auxiliary Keyer (Loop 2), could also be used to switch any
data circuit requiring a switch-to-ground operation on mark within the ratings of the transistors
(+200 Volts, 100 mA maximum). The Main Keyer (Loop 1) has the loop sense emitter resistor and
therefore may not "pull-down" sufficiently when a high current load is switched,
3.3.2. Separate Printer and Keyboard Connections
As mentioned previously in section 3.2.6, the keyboard contacts or keying circuit can be sepa-
rated from the printer circuit if desired. To do this, connect the printer (or display) to the loop or
RS-232 circuit as the conditions require and the keyboard circuit to the keyboard connections avail-
able on the AUXILIARY, or KOS, or LOOP 1 & 2 connector, The standard cables include a keyboard
connection through the KOS connector. The keyboard circuit should be isolated from the loop and
use either contacts or an NPN switching transistor to ground. The separate keyboard data is
sensed by the KOS circuit and therefore all KOS features are available with this connection. Note,
however, that a jumper on the AUXILIARY jumper plug should be removed for separate keyboard
data input: carefully cut the path on the AUXILIARY jumper circuit board between pins 1 and 5
with a sharp knife or scribe.
3.3.3 Full Duplex Operation of the ST-6000
The receive (demodulator) and transmit (tone keyer) sections of the ST-6000 are normally inter-
connected with the standard cables and jumpers so that all keyboard generated data automatically
drives the transmit data circuits to use a "full-duplex" mode of operation. To connect the ST-6000
for full-duplex operation, remove the jumpers on the AUXILIARY jumper plug between pins 1 and
5 and between pins 11 and 15. Add a jumper to the AUXILIARY jumper plug between pins 14 and
15. The separate keyboard should now be connected as described above in sect ion 3.3.3. Re-
ceived data will now be displayed on the printer or visual display system but will NOT key the tone
keyer section. Keyboard data will trigger the KOS circuit and key the tone keyer section. The same
connections can be used for full-duplex operation with either RS-232 or MIL-188 signal levels if the
appropriate connections on the rear panel connector are selected. Connection of the separate key-
board, and full-duplex jumpers are shown in Figure 3.6. Since the KOS circuit also places the ST-
6000 in standby condition, KOS should be switched OFF for true full-duplex operation.