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3 pin dmx cables


richardc1983

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Come on guys, the OP just asked a simple question,

 

Anyone on here sell cables, need 3 x 1.5 metre approx, 1 x 6mtr and 2 x 10metre.

 

Let me know prices etc need to order asap thank you

 

very short, sharp and brusque, which dosen't go down well with BR Members, understandably, a bit of correct grammar and a please or thank you wouldn't go amiss.

 

The obvious answer should have been, no we don't we're technicians not retailers.

 

The only person who seems to have answered the OPs question is Paulears, everyone else just seemed to jump on the guys back because he'd said '3 pin DMX'.

 

Again let's be honest, unless you work in this industry in a professional capacity you're unlikely to know that DMX uses 5 pin XLRs and who of us hasn't used a '3 pin DMX' connector and didn't know what the OP was refering to.

 

No Paul we're not a Pro. Forum we are a Public Forum and anybody from a ten year old school boy to a highly qualified technician can post on here, which at times raises other problems, as professional BR Members know.

 

How about us all being a bit more accomodating with the youngsters and the ill informed who join the BR, gently steering them to the truth rather than be-littling them, some of them are going to be the industries future.

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Cabling has been removed from the document and will be in one or more separate standards documents (BSR E1.27-1 -- Portable Control Cables for Use with USITT DMX512/1990 and E1.11 [DMX512-A] Products - has been approved by the E1 Accredited Standards Committee. Final ANSI approval is expected in the spring of 2006

No mention of connectors being removed from DMX512A ... just cabling ...

 

Anyway, if the connectors and cabling have been annexed to a separate document that's so closely linked to the standard itself, then surely they're still effectively part of the standard as far as the real world is concerned?

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I can't post the released DMX-512-A but the draft copy was :

 

6 Electrical Specifications and Physical Layer

6.1 General

This standard addresses portable cables for use in DMX512 systems that conform to EIA-485 and additional physical layer requirements. Where a conflict exists, DMX512-A shall govern. The physical layer of a DMX512 data link is constrained by earth grounding practices, termination methods, signal levels, EMI, and accidental damage by connection to other devices.

6.2 DMX512 Portable Cables

6.2.1 General

A DMX512 Portable Cable is a digital data transmission cable designed for the provisional interconnection of two DMX512 devices. Portable cables shall each have two prescribed connectors, a male 5-pin XLR at the end nearest the transmitting device and a female 5-pin XLR at the end nearest the receiving device. Pins shall be designated 1 through 5. All five pins shall be connected and there shall be no connection to the shell.

6.2.2 Compatibility with Legacy Equipment

Some legacy equipment placed voltages on the second pair of data conductors that may damage other connected DMX512 devices. Portable adaptors intended to break the second pair for the purpose of protecting DMX512 devices are beyond the scope of this standard.

6.3 Data link common and grounding topologies

In all cases Pin 1 of DMX512 portable cable connectors shall act as Data Link Common. The wire connected to Pin 1 shall be no smaller than the wire used for the twisted pairs in the cable.

6.4 Data Link signal designations summary

Table 1 - Signal designations summary

Use

5-Pin XLR Pin

DMX512 Function

Common Reference

1 Data Link Common

2 Data 1 - Primary Data Link

3 Data 1 +

4 Data 2 - Secondary Data Link

5 Data 2 +

 

7 Required Disclosures

7.1 Portable Cable Disclosures

Portable DMX512 cables shall come with the following declaration: “Complies with ANSI E1.27-1 – Standard for Portable Control Cables for use with USITT DMX512 and ANSI E1.11 – USITT DMX512-A Products”.

The cable assembly shall be marked with "ANSI E1.27-1" in a durable manner.

 

There is provision for RJ 11 ? connectors for some areas of disco lighting but 3 pin "cannon" connectors were not included.

 

Please note in physical layer "and accidental damage by connection to other devices." hence the need to exclude 3 pin "cannon" connectors from DMX leads.

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The gist of the current spec is that you must use the XLR5 connector, unless you don't have space to physically accomodate an XLR, in which case you can use any other sort of connector you like, except... any type of XLR connector other than a 5 pin. So XLR3s are not acceptable under the current spec.
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jesus!! all this chibber chabber from an original fairly straight forward question from someone not to sure about the correct terminology.

 

In that case anybody getting picky about 3 or 5 pin DMX / data leads should point out to several leading moving light companies that all their fixtures should only have 5 pin connectors on them if they are going to call one method of control "DMX protcol" or "this fixture has xx DMX control channels" (even though it might have 3 pin XLR connectors on the side!!! )

 

 

Give Me Strength!!!!

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It always amazes me how as soon as someone writes a post with "DMX" in the title everyone jumps on the whats right or wrong bandwagon with cables and connectors!

 

I myself have been shot down in flames by a regular poster in these forums for answering the original posters question with a honest answer as I saw it!

 

A handfull of people dominate this forum and I for one don't think this "handfull" are always right!

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Skier,

 

I'm not a lampy, so I don't have an axe to grind...

 

However, I do value the introduction and use of standards, and I can see a very strong logic for maintaining the specified cable and connector types for correct operation and compatibility. Having just watched a group of students spend hours trying to interface different lighting products, I can only hope that the standard is actually applied.

 

With regards to the "dominant handful" - well if they make ths place disciplined and well behaved, and ensure useful informative posts, then I take my hat off to them. After all, we're here as guests aren't we? It would be impolite in the real world to join a conversation between established friends, then tell them that they were wrong and 'dominant'....

 

Simon

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