Help Centre FAQs DMX / RDM Can I run DMX512 over Cat5 cables?
Can I run DMX512 over Cat5 cables? PDF Print E-mail

 

One of the most common cables found these days in buildings is the humble Cat5 cable.
It's use in computer networks means that it has had found wide appeal, to the point where the average electrician is comfortable in using it and terminating it.

Due to its common use, questions are often asked about running other types of signals over this type of cable. Naturally enough the question of running DMX512 over Cat5 has also been asked.

ESTA, a suppliers association in the US (LSC is a member) many years ago took on the responsibilty of overseeing the development of standards for our industry. When this question was raised some 10 years ago, a Task Group was formed to do practical testing on DMX512 signals over Cat5 cable to see what the results would be.

The Task Group's mission was to employ an independent laboratory to carry out a series of comparison tests between a typical cable presently used for hardwired DMX512 installations, and conventional Category 5 data cable. The goal of this testing was to establish whether Category 5 cable could be used as a low cost substitute in permanently wired DMX512 installations. Two series of lab tests were conducted in July and November of 1998 at MPB Technologies in Airdrie, Alberta. Additional tests were conducted in December of 1999.

Data obtained from all three of these test sessions confirms that, in most respects,
UTP and STP Category 5 cable can be expected to perform at least as well as EIA-485 rated data cable for DMX512 applications.


For the technically minded, a summary of the three reports is available on the ESTA website here (PDF, 15kB). It describes the tests and gives general conclusions.

Part 1 of the report (PDF, 1.07MB) gives the details of the first series of tests that compared the DMX512 handling characteristics of a typical EIA-422 rated data cable with those of a standard Category 5 unshielded twisted pair (UTP) cable. Radiated emissions tests were also done. Results of these tests indicated that Category 5 UTP cable performed as well as conventional DMX512 cable.

Part 2 of the report (PDF, 429kB) details the second series of tests that were carried out with Category 5 shielded twisted pair (STP) cable, and also included radiated and induced signal immunity tests to current IEC standards on all cable types.

Part 3 of this report (PDF, 390kB) details the third series of tests that were conducted to determine the effect of combining different types of cable (i.e., Category 5 and EIA-485) on the same wire run. At this time, tests were also done with Rosco/ET IPS equipment to determine whether the use of Category 5 cable caused any timing problems with the talkback data.


The Technical Standards Committee of ESTA has in recent years produced an ANSI standard for DMX512 wiring including over Cat5 cables.

The standard is known as ANSI E1.27-1 - 2006 and its title is
Entertainment Technology-Standard for Portable Control Cables for Use with USITT DMX512/1990 and E1.11 (DMX512-A) Products.

A copy of this standard can be purchased from ESTA's online website.

Last Updated ( Monday, 05 March 2018 11:14 )
 

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