9
The DMX standard ANSI E1.11 suggests that transmitters are “ground referenced”. With the ISP-‐4, this is achieved
for each output port by wiring pin 3 to pin 4.
In some cases, however, the above configuration may lead to so called ground loops. This applies when a DMX
receiver’s COM input signal is connected to the earth with a low resistance. In such cases it may resolve issues by
not connecting pin 3 to pin 4 of the corresponding output.
Note: Only with the latter setup, each output port is individually optically isolated, meaning that it is totally
isolated from the other output ports and from the input section.
Models with RJ45 Connectors
The RJ45 versions ISP-‐4D-‐DC-‐RJ45A, ISP-‐4R-‐DC-‐RJ45A, ISP-‐4D-‐DC-‐RJ45B and ISP-‐4R-‐DC-‐RJ45B are configured as
“isolated” transmitters as defined in ANSI E1.11, such that each output port is individually optically isolated, meaning
that it is totally isolated from the other output ports and from the input section.
ANSIE1.11 compliant RJ45 configuration, applies to
ISP4X-‐DC-‐RJ45A models.
Alternative RJ45 configuration, applies to ISP-‐4X-‐RJ45B models.
Line Termination
The line termination of the ISP-‐4 splitters may be turned on or off using the toggle button next to the through port.
See page 7. The line termination should be turned on by pushing it down when no receiver is connected to the
through port of an ISP-‐4, and turned off otherwise.
Pin
Connection
1
Data +
2
Data -‐
3
Not connected
4
Not connected
5
Not connected
6
Not connected
7
Com
8
Com
Shield
Earth
Pin
Connection
1
Data -‐
2
Data +
3
Com
4
Not connected
5
Not connected
6
Not connected
7
Not connected
8
Not connected
Shield
Earth
