
Chapter 1
SYSTEM SUMMARY
1-4
[Rear]
1
2
ECH
AUDIO OUTPUT
ECH
AUDIO INPUT
ECH ECH
GND
SIGNAL
LAN
AC ADAPTERDC INPUT
DC INPUT
109
CONTROL INPUT
CONTROL OUTPUT
12345 8C67
12345 8C67
ON
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1212
GND LIFT LINE
PAD
MIC
NORMAL
12. Signal GND terminal
Be sure this terminal is securely grounded.
Note: This terminal is not for protective ground.
13. DC power input terminal
A 24 V DC input.
14. AC adapter terminal
Connects to the optional AD-246 AC Adapter or
the equivalent.
As for the usable adapter, consult your TOA
dealer.
15. Network connection terminal
Connects to 10BASE-T or 100BASE-TX networks.
(RJ-45 Ethernet jack)
16. Control output terminal (9, 10)
Relay contact outputs (withstand voltage: 30 V
DC, control current: 0.5 A maximum).
17. Control output terminal (1 – 8)
An open collector output (withstand voltage: 30 V
DC, control current: 50 mA maximum).
18. Audio output terminal
0 dB*, under 600 Ω, balanced type.
Provide audio signals of line signal level.
H: Hot, C: Cold, E: Earth (shield)
19. Cord clamp
Pinches and securely holds the AC adapter cord
to prevent its plug from detaching.
20. Control input terminal
No-voltage make contact input (short-circuit
current: under 2 mA; open-circuit voltage: 24 V).
21. Audio input terminal
−20 dB* for line signal level, −60 dB* for microphone
signal level, 2 kΩ, balanced/unbalanced switchable.
Receive audio signals of microphone or line signal
level.
H: Hot, C: Cold, E: Earth (shield)
22. DIP switch for equipment settings
Used when performing audio input settings.
[Default DIP switch setting]
•Switch 1
Ground lift selection switch
(NORMAL/GND LIFT)
A ground loop can potentially be created when
the NX-300 is connected to other equipment,
resulting in a hum noise. Ground loops can be
cut off by setting this switch to GND LIFT (lower
position). Settings are common to both Audio
Inputs 1 and 2. This switch is factory-preset to
NORMAL (upper position).
•Switches 2 – 4
Not used.
These switches are factory-preset to OFF (lower
position). Always keep them to the OFF (lower
position).
•Switches 5, 6
Audio input pad setting switch (PAD)
Enables or disables the audio input pad (−16
dB). When the input level is large, set the PAD
to ON (upper position). These switches are
factory-preset to OFF (lower position). Switch
5 (PAD 1) corresponds to Audio Input 1 and
Switch 6 (PAD 2) corresponds to Audio Input 2.
•Switches 7, 8
Audio input level selection switch
(MIC/LINE)
Set these switches to MIC (upper position) when
a microphone is connected, and to LINE (lower
position) in other cases.
These switches are factory-preset to LINE
(lower position). Switch 7 (MIC 1) corresponds to
Audio Input 1 and Switch 8 (MIC 2) corresponds
to Audio Input 2.
* 0 dB = 1 V
ON
12345678
GND LIFT LINE
PAD
1212
MIC
NORMAL