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AES DIGISWITCH 3X1

                             

HENRY ENGINEERING 

THREE-INPUT AES DIGITAL AUDIO SWITCHER

 

 

              

                    PO Box 3796 

Seal Beach, CA 90740 

Tel: 562.493.3589 

 

                                              

         www.henryeng.com 

 
DESCRIPTION 

AES DigiSwitch 3X1 is a three-input digital audio switcher.  It accepts up to three AES digital audio sources, 
selecting one source that is routed to the AES output.  It can be used as an AES source selector, or "in reverse" as 
a router, sending an AES source to one of three destinations.  All switching is via sealed relays. There is no active 
circuitry in the signal path, hence all data remains bit-accurate with no added delay or latency. The unit can be 
controlled by front panel pushbuttons and/or by any remote switch or contact closure, TTL/CMOS logic, or DC 
voltage. Internal power-up programming permits the user to determine which input is automatically selected when 
AC is applied. An optional Auto-Return mode automatically selects Input #1 if no other input is selected. Tally 
outputs are provided to drive remote status LEDs.  Input sources that are not selected are automatically terminated. 
 

WARNING! For 230V operation, change mains voltage jumpers before connecting to AC power!   

Remove jumpers between E6 & E7, and between E5 & E8.  Install a jumper between E5 & E6 for 230V; replace 
fuse with a .125a fuse. See schematic on reverse side.  Jumpers should be changed by a qualified technician only. 

 

INSTALLATION 

All AES I/O is via standard XLR connectors.  Pin 1 of all XLRs is connected to the AC safety ground and the units chassis. 
 
AES DigiSwitch 3X1 can be controlled with any contact closure, open-collector, or by applying a DC voltage (5 - 24 VDC) from 
an external source, e.g., the TTL or CMOS-level output of a computer interface or a logic circuit. Control inputs can be either 
momentary or maintained.   
 

Control logic programming: 

Before connecting control inputs, the user must determine the type of control that will be used, 

and configure internal programming jumpers accordingly.  There are 3 Control inputs, one for each audio source.  Each Control 
input can be set to accept one of 3 types of control input:  (1) a contact closure that switches to ground, (2) a contact closure 
that switches to a positive voltage, or (3) a DC voltage between 5 and 24 VDC. 
 
The programming jumpers are located within the unit just behind the front panel. They and are marked JP1, JP2, and JP3, for 
Control inputs #1, #2 and #3.  Each set of programming jumpers has pin-pairs labeled 

A, B, and P. 

 

To configure an input for control via 

any circuit that switches to a positive voltage, or to control by applying a DC voltage: 

Install two jumpers in the 

A

 positions.  To configure an input for control via 

any circuit that switches to ground: 

Install two 

jumpers in the 

positions.  (DigiSwitch is shipped with this configuration preset.) 

 
Connect Control inputs via the 9-pin D connector as follows: 
 
Pin 1 

Control #1 input   

 

Pin 4 

Ground   

 

 

Pin 7 

Tally #1 output 

Pin 2 

Control #2 input   

 

Pin 5 

+12 VDC source   

 

Pin 8 

Tally #2 output 

 

 

Pin 3 

Control #3 input   

 

Pin 6 

Remote Disable   

 

Pin 9 

Tally #3 output 

 
Connect all control input signals between pin 4 (ground) and the desired Control input pin. For open-collector interface, connect 
the emitter to pin 4 (Ground), and connect the open-collector to the appropriate Control input. 
 

Power-up programming:  

Each set of programming jumpers has a 

P

 option to set the power-up programming.  The input that 

is selected with the 

P

 jumper will be automatically selected upon power-up.  Install a 

P

 jumper in 

one input only.

  DigiSwitch is 

shipped from the factory with the Input #1 

P

 jumper set for power-up. 

 

Auto-Return mode:

  AES DigiSwitch 3X1 can be configured to return to Input #1 if no other input is selected.  This would be 

applicable if external equipment provides a 

maintained

 closure when switching should occur, and the 

release

 of this closure is 

used to return to input #1.  To use the Auto-Return mode, 4 components must be installed on the DigiSwitch PC board:  Two 
1N4004 diodes (D6, D7), one 10K resistor (R3), and one 35uf/25v capacitor (C2).  Install these components on the PC board 
where indicated.  Observe polarity. 

 

NOTE: ALL of the power-up “P” jumpers must be removed when the Auto-Return mode is used

 
To use the Auto-Return mode, ALL Control inputs 

must be configured for ground-closure use, 

with jumpers in the

 B 

positions.  Control inputs to #2 and/or #3 must be ground closures.  Connect between pin 4 (ground) and the appropriate Control 
input.  DO NOT connect anything to Control input #1 (pin 1).  

Remove the “P” jumper. 

 

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