Editing DMX512 (section)

=== Electrical ===
<!-- Before revising this paragraph, please see section "Direct quotes from standards" on the talk page -->DMX512 data is transmitted over a differential pair using [[EIA-485]] voltage levels. DMX512 electrical specifications are identical to those of the EIA-485-A standard, except where stated otherwise in E1.11{{For example?|date=December 2018}}.

DMX512 is a [[bus network]] no more than {{convert|400|m}} long, with not more than 32 unit loads (individual devices connected) on a single bus. If more than 32 unit loads need to communicate, the network can be expanded across parallel buses using DMX splitters. Network wiring consists of a shielded [[twisted pair]], with a characteristic impedance of {{val|120|u=Ω}}, with a termination resistor at the end of the cable furthest from the controller to absorb signal reflections. DMX512 has two twisted pair data paths, although the specification currently only defines the use of one of the twisted pairs. The second pair is undefined but required by the electrical specification.

The E1.11 (DMX512 2004) electrical specification addresses the connection of DMX512 signal common to earth ground. Specifically, the standard recommends that transmitter ports (DMX512 controller OUT port) have a low impedance connection between signal common and ground; such ports are referred to as ''grounded''. It is further recommended that receivers have a high impedance connection between signal common and ground; such ports are referred to as ''isolated''.

The standard also allows for isolated transmitter ports and non-isolated receivers. It also recommends that systems ground the signal common at only one point, in order to avoid the formation of disruptive [[ground loop (electricity)|ground loops]].

Grounded receivers that have a hard connection between signal common and ground are permitted but their use is strongly discouraged. Several possible grounding configurations that are commonly used with EIA485 are specifically disallowed by E1.11.