Klein + Hummel K8-AI8, Operating Manual

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K8 Rackmount Family User Manual Page
17
Overview
The K8-AO2 is a K8 output device for receiving 2 audio channels from the K8 bus and decoding them into 2
analogue outputs.
Routing Capabilities
As shipped from the factory, the K8-AO2 will place audio channels 1,2 on outputs 1,2.
The two outputs of the AO2 device can select any stereo pair from the K8 bus. A stereo pair must be
adjacent channels and begin with an odd numbered channel. For example, channels 1 and 2, 3 and 4, 5
and 6 and so forth are all valid.
Stacking Output Devices
The K8 bus supports a maximum quantity of 254 devices. Output devices may be daisy chained until the
maximum cable length of 200 meters has been reached. Output devices are passively connected and do
not refresh the K8 audio signal. This architecture has the benefit that a failure of an output device will still
allow audio to pass to the next device in the chain. Daisy chaining devices introduces no delay in the audio
signal.
Termination Setting
All 4 termination switches must be set to “on” when the AO2 is the last device in the K8 chain.
K8 link port connected:
Termination Off
K8 link port not connected: Termination On
Control and Monitoring
All devices on the K8 bus may be controlled and monitored through a single RS-485 connection to the AI8
device. The protocol is openly published on
www.klein-hummel.com for use by software engineers and
control system programmers. The pinout of the RS-485 port is as follows:
PIN 1 Phantom Ground
PIN 2 Phantom Power
PIN 3 Data A (+)
PIN 4 Data B (-)
PIN 5 Signal Ground
PIN 6-9 Not Used
A limited amount of serial data tunnelling is available between the serial ports on any two devices in the
system. This is useful for passing control data to another system, such as a lighting controller or external
relay box located in the same equipment area as the K8 output box.
The phantom power is used to drive K8 accessories designed to attach to the local control connector, such
as a local volume control wall plate. Phantom power is switched off by default and must be activated
through the control protocol.
Output Level Settings
The AO2 is shipped from the factory to provide a +4 dBu nominal output level with a peak level of +22 dBu
on the XLR and terminal block connectors. By default, the same signal level fed into an analogue input AI8
will appear at an analogue output AO2 at the same level.
The RCA cinch connectors are factory set to provide a –10 dBV nominal output level.
DB9 Female Control Connector