REVISION C
BMX SERIES III CONSOLE
69
PACIFIC RESEARCH & ENGINEERING
The remote control cough muting function is achieved by pulling low the appropriate A or B cough line,
which is selected by U201, and routed through U215B to U215A. Whenever any of the inputs to U215A
are low, the “on” tally lights are extinguished and the channel outputs are muted. When the cough line
is released, the outputs are unmuted and the “on” lamps illuminated.
Pressing the CUE button gives a high output from U207B to CUE bistable U210A. When the CUE
function is engaged, U210A output pin 1 goes high to turn on CUE relay K3, and pull the CUE command
bus low via Q203. Output pin 2 goes low and is routed to Control Room monitor mute selector U206B.
A Control Room microphone selection causes a high at the output of U206, saturating Q200, and pulling
down the Control Room mute bus to prevent feedback. This change of state is also routed to network
C222 and R223, through U209A, to reset SOLO bistable U210B if this function was engaged. The CUE
bistable output is also coupled to a lamp flashing circuit for the CUE lamp. The lamp flashing circuit
may be defeated by strapping together points E200 and E201 on the printed circuit board. The module
will be taken out of the CUE mode when the channel ON button is pressed, if CUE RESET ENABLE
switch S204B pins 2 and 3 are closed.
Pressing the SOLO button gives a high output from U207C to SOLO bistable U210B. When the SOLO
function is engaged, U210B output pin 13 goes high to turn on SOLO relay K6, and pull the SOLO
command bus low via Q204. Output pin 12 goes low and is routed to Control Room monitor mute
selector U206B. A Control Room microphone selection will causes a high at the output of U206B,
saturating Q200, and pulling down the Control Room mute bus to prevent feedback. The change of state
is also routed to network C219 and R220, through U209B, to reset CUE bistable U210A, if the CUE
function was engaged. The low at pin 12 also drives Q206 to turn on the lamp in the SOLO button. The
module will be taken out of the SOLO mode when the channel ON button is pressed, if SOLO RESET
ENABLE switch S204A pins 1 and 4 are closed.
A remote control “privacy” mode is available which prevents the module from being able to enter the
CUE or SOLO functions. This INHIBIT function is routed from logic input selector U201 through
U208 to both U209A and U209B. The inhibit function puts a high into the reset inputs of both the CUE
and SOLO bistables to lock them in the “off” mode.
Circuit U200 selects the input A and B Talkback selection functions. Pin 14 is low for Talkback to the
Control Room, pin 4 for Studio-1, pin 5 for Studio-2, and pin 13 for the External location. Circuit U202
is used as the input microphone location status selector, as determined by module programming switch
S207. Pin 13 will be low for a Control Room microphone, pin 14 for Studio-1, pin 4 for Studio-2, and
pin 5 for the External location. The outputs of U200 and U202 are routed to gates U203, U204, U205,
and U206B. These gates provide the logic controls for a location to Talk to any other location, dim the
monitor levels at the originating location, and command the Talkback function at the destination
location.
For an input module to Talk to the Control Room, one of the Talk to Control Room lines is pulled low
by a “Talk to Control Room” push-button switch. This will cause a low at U200 pin 14, which is routed
to U203 pin 1, which will generate a low output at U203 pin 7. The low at U203 pin 7 is routed to U215A
pin 3, giving a low at the output of U215A, which is routed to U215B. The “on” tally circuit will be
de-energized. The low at U203 pin 7, via inverter U213F, saturates Q221, pulling down the Talk to