User manual

8 Installation
To build the serial link
1. Use shielded twisted-pair cable. A reliable data connection begins with the right
cable. Microphone cable cannot transmit DMX data reliably over long runs. For best
results, use only cable designed for RS-485 applications. Your Martin dealer has a
range of cables, connectors, and adaptors designed for lighting control.
2. Starting from the controller, connect output to input. Four parallel DMX out-
puts, two 3-pin, and two 5-pin are provided on the Freekie.
3. Never use a “Y” connector to split the link. If you need to split the serial link
into branches use a dedicated splitter/amplifier such as the Martin 4-Channel
Opto-Isolated RS-485 Splitter.
4. Don’t overload the link. Placing more than 32 devices on a link can cause
unpredictable performance.
5. Always terminate the link by installing a termination plug in the output socket
of the last fixture on the link. The termination plug, which is a male XLR connec-
tor with a 120 ohm resistor soldered between pins 2 and 3, “soaks up” the con-
trol signal so it cannot reflect back down the link. If a splitter is used, terminate
each branch of the link.