Studio Technologies 78 2004 - Manual (Page 37)

Model 78/79 User Guide Issue 5, January 2004
Studio Technologies, Inc. Page 37
for Surround
audio equipment. The dBV designation re-
fers to dB referenced to 1.0 V, rather than
dBu which refers to 0.775 V.
“Hot” Disconnection of the
Model 79 Control Console
Should you need to relocate the Model 79
while your StudioComm system is operat-
ing, there is no reason why you can’t dis-
connect the cable, move the unit, and then
connect it again. If the Model 79 is discon-
nected while it is operating, the current
operating parameters are saved in non-
volatile memory and the Model 78 Central
Controller will continue to operate as be-
fore the connection was broken. No clicks,
pops, or other noises will occur when the
Model 79 is again connected. The Model
79 will go through its standard power-
up sequence, send a message to reset
power-up defaults, then send the operating
parameters as stored in its memory.
Monitor Output Transient
Protection
The Model 78 Central Controller contains
a power up/power down transient protec-
tion feature. This limits the chance of dam-
age to the monitor loudspeakers during the
time when AC mains voltage is connected,
disconnected, or has changed significantly
from nominal. A combination of hardware
and software is used to monitor one of the
power supply “rails.” Until the AC mains
input exceeds approximately 69% of its
nominal voltage, electromechanical relays
maintain a short circuit condition on the
monitor outputs. After a short delay the
relays are allowed to function normally.
Whenever the AC mains input drops below
approximately 67% of its nominal voltage,
the relays immediately go to their mute
Pin Signal Direction
1 Power Supply Common 78 to/from 79
2 +15 Vdc 78 to 79
3 Data (MIDI System-Exclusive) 79 to 78
4 Data Common 79 to/from 78
5 Remote Mute All 78 to 79 (Note 2)
6 Remote Dim 78 to 79 (Note 2)
7 Remote Input Select 78 to 79 (Note 2)
9 Remote Control Common 78 to/from 79
Notes: 1) Connector types on Model 78 and Model 79 are
9-pin D-subminiature female. Connectors use 4-40
threaded inserts for locking with mating plug.
2) Remote control sources connect to D-sub on
Model 78, then passively route to Model 79 via
78/79 interface D-sub.
Figure 9. Connections between Model 78 and
Model 79
state. During testing it was found that upon
power up the monitor outputs remained
very quiet; during power down a moderate
“tick” was the worst that was heard.
Model 78 to Model 79
Connections
Figure 9 gives a detailed view of the sig-
nals that connect between the Model 78
Central Controller and the Model 79
Control Console. The Model 78 provides
+15 Vdc power for the Model 79. The
Model 79 generates MIDI system-exclusive
messages and sends them to the Model
78. From the outside world, the remote
control input sources connect to the Model
78. They then route, via the interface cable,
from the Model 78 to the actual input cir-
cuitry, located in the Model 79.