Studio Technologies 76DBA V.3.00 - Manual (Page 16)

Issue 1, November 2010 Model 76DBA/77B User Guide
Page 16 Studio Technologies, Inc.
for Surround
Remote Control Inputs
Support is provided for three remote
control input functions: remote mute all,
remote dim, and remote auxiliary stereo
monitor output on/off. Note that the remote
mute all and remote dim functions only
impact the post-fader surround digital and
analog monitor outputs.
The Model 76DBA’s inputs use logic gates,
“pulled up” to +5 volts DC by way of resis-
tors, which are active whenever they are
brought to their logic low state. Inputs of
this type are commonly referred to as GPI
inputs. While the input circuitry is protected
from over-current and static (ESD) dis-
charge, care should be taken to prevent
nasty signals from reaching them. The
inputs are active only when held in the low
state; they can’t be configured to change
state (“latch”) in response to a logic pulse.
The same 9-pin D-subminiature connec-
tor used for the metadata input is also
used for the remote control inputs. Refer
to Figure 6 or Appendix A for the exact
connection details. Note that pin 4 (remote
common) connects to the Model 76DBA’s
internal circuit common connection as
well as to the Model 76DBA’s chassis and
mains earth connections. Figure 6 also
shows one spare remote control input
(pin 9). This is provided for future applica-
tions and should remain unconnected.
Connecting the Model 76DBA
to the Model 77B
A 9-pin female D-subminiature connec-
tor, labeled To/From Control Consoles, is
provided on the back panel of the Model
76DBA Central Controller. This is used to
interface the unit with Model 77B Control
Consoles. Refer to Figure 7 or Appendix A
for details. A 9-pin female D-sub connector,
labeled To/From Central Controller, is pro-
vided on the back panel of each Model 77B
Control Console. A cable with 9-pin male
D-sub (DE-9M) connectors on each end is
used to interconnect the Model 76DBA with
the Model 77B units. A cable is included in
the shipping carton. The cable implements
all nine connector pins in a one-to-one
manner.
Should an interconnecting cable of a differ-
ent length be required there’s no problem
for one to be fabricated and used. While it
can be wired in a one-to-one fashion sup-
porting all nine pins, only four connections
are required: pin 1 (data +), pin 6 (data –),
pin 4 (DC +), and pin 9 (DC –). The Model
76DBA’s connector pin-out scheme was
designed to allow creation of an inter-
connecting cable which uses commonly
available 2-pair audio cable. This cable,
consisting of two twisted pairs each with an
individual shield, is typically sleek, flexible,
and available in many colors. One pair and
shield can be used for the data connections
while the other pair and shield can be used
for the DC connections. This implementa-
tion has the advantages of providing a
shield for the data path and a more robust
common connection (two conductors in-
cluding the shield) for the DC power circuit.
Signal Pin Direction
Data + (RS-485) 1 To/From Models 77B/71
Data – (RS-485) 6 To/From Models 77B/71
Data Shield 2 To/From Models 77B/71
DC + (12 V) 4 To Models 77B/71
DC – (12 V Return) 9 To Models 77B/71
DC Power Shield 5 To/From Models 77B/71
Note: Connector type on Model 76DBA is 9-pin D-subminiature
female (DE-9F). Connector uses 4-40 threaded inserts
for locking with mating plug.
Figure 7. Connections between Model 76DBA
and Model 77B and Model 71