ALLEN & HEATH GL2200 SYS-LINK Application Note

GL2200
MIXING CONSOLE

THE BENEFITS OF USING SYS-LINK

The GL2200 SYS-LINK option allows console to console interconnection by means of
just one or two cables. By connecting two GL2200 consoles together the number of
input channels may be increased. One console acts as a channel expander (slave) to
the second (master). Up to 3 consoles may be 'daisy-chained' in this way. The system
is also directly compatible with other A&H consoles fitted with SYS-LINK.
Plugging consoles together using SYS-LINK connects the signals directly to the
console busses so avoiding the use of the main console outputs and channel inputs for
the master / slave connection. All the console channels are available to the user for
input sources.

SYS-LINK CONNECTIONS

SYS-LINK connects all the console main busses including the L, R, 4 Groups, and 6
Aux sends. The PFL/AFL system is also interconnected such that operating PFL/AFL
on the slave console activates the master console monitor system. Operating PFL/AFL
on the master does not activate the slave monitor system which may be used for 'local'
monitoring if required. SYS-LINK connects the PFL/AFL audio mix and DC control
buss.
SYS-LINK outputs are taken pre-fader so that the slave console output connectors
may be used for sub-mix or 'zone' feeds if required. All output signals are unbalanced,
low impedance and operate at a line level of –2dBu to prevent problems with audio
interference and to maintain a headroom of 23dB.
SYS-LINK inputs are unbalanced, operate line level at –2dBu and are high impedance
to prevent loading the connected source.
SYS-LINK is presented on two 25way female D-type connectors, one for the console
buss inputs and the other for the outputs. Several pins are provided for audio 0V earth.

USING SYS-LINK

Connect consoles using two standard 25way male to male D-type cables, available
from electronic suppliers or computer shops (25line male to male). It is advised that
this cable is a screened type if longer than 1 metre, no longer than 10 metres in total,
and that professional quality locking connectors are used. Connect all pins one to one
with the screen to 0V.
Connect the slave console SYS-LINK output to the master console SYS-LINK input.
SYS-LINK may also be used to connect the GL2200 to other audio equipment. Make
sure that all unused inputs (except the P/AFL DC inputs) are linked to 0V earth at the
SYS-LINK input to prevent audible interference from connected audio signals.
Connect line level signals of around –2dBu. The GL2200 PFL/AFL system may be
activated by switching the P/AFL DC input to 0V earth through a 15k ohm resistor.
For information on fitting SYS-LINK please refer to FITTING INSTRUCTIONS AP3622.
SYS-LINK APPLICATIONS NOTE
Publication AP3623
I 1 JAN 99
SSUE