[Coco] WiFi modem.

Dave Philipsen dave at davebiz.com
Fri Jan 19 12:10:12 EST 2018


Allen, DMX512 *is* RS485 but RS485 only defines the transmission of the data. The most critical part of DMX512 is the protocol in making sure the timing is correct with the data at 250 kbps and the break timing. 

Perhaps some of the problems with the cheap RS485 converters is that they are set up for "standard" protocols. I routinely use a very inexpensive RS485 driver chip to transmit DMX512 signals and it has worked in 100s of installations.

Dave

On Jan 19, 2018, at 9:39 AM, Allen Huffman <alsplace at pobox.com> wrote:

>> On Jan 19, 2018, at 9:32 AM, Gene Heskett <gheskett at shentel.net> wrote:
>> 
>> I might point out that fleabay also has RS485 plugins that are 4 wire ttl 
>> on one end, power, ground, send and receive, and the differential 2 wire 
>> rs485 on the other, giving a megabaud+ capable path, half duplex for 
>> about a buck a copy.
> 
> At my previous job, I worked on RS485 and Modbus protocol. At my current job, we use RS485 for communicating between Power-over-Ethernet “smart building” controllers. RS485 is also used for DMX lighting, which I also have worked with.
> 
> I have found some of these cheap USB-RS485 have issues working with DMX (which may explain why DMX interfaces are so stupidly expensive).
> 
> You are suggesting using something like RS485 between CoCo and a PC with a cheap interface, rather than RS232? 
> 
>        — A
> 
> 
> 
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