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aleandro greete
on Feb 3, 2017 at 12:43:44 am

I have some old equipmant from BFE, Philips that uses a protocol called ES BUS, it looks like a 15 pin DB style connector (one for IN and another for OUT).
If someone have any info about this protocol, I'm really curious, I cannot find any info on the net!
Thanks in advance!

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aleandro greete
Re: ES BUS from BFE
on Feb 18, 2017 at 6:11:25 pm

I'm very surprised, using google have found almost zero but there's tons of this equipment around that uses this bus (and more recent ones like ESNet and nowadays ethernet).
This is what I've discover so far.
ESbus is a communication system developed specifically for the remote control of television equipment.
It is the joint work of the Society of Motion Picture and Television Engineers (SMPTE) and the European Broadcast Union (EBU).
The ESbus provides a means for anywhere from two to a large number of devices to communicate with each other in a very flexible manner over a common bus.
The bus consists of two twisted pairs that carry data at 38.4K baud, even parity, RS-422.
Its uses a 9-pin D connector (but in my case a 15-pin one!)
The ESbus uses a Break character as an attention signal to establish communication between a tributary and the controller.
This protocol provides the greatest protection (though no correction) from communication errors.

Reverse engineering the mainboard I've got this info from my 15-pin sub:
1: GND
2: GND
3: Chassis Ground
4: A2(+)
5: B2(-)
6: -nc-
7: GND
8: -nc-
9: +24
10: +24
11: Chassis Ground
12: A1(+)
13: B1(-)
14: -nc-
15: GND
(this is BFE BD51-LC/Z2 In connector, the Out one looks like paralled!)
The A/B should be read as A=+ and B=-, internally are connected to a LTC4851 used as RS422 transceiver at 0..5V.
The protocol should be RS422 but I still not discover witch couple between A1/B1 or A2/B2 is the trasmitter or reader.
I've also get this infos by carefully reading as much I can from services manual of old video desk:

Baud: 38400, start/stop bit:1, parity:ODD

The ESbus protocol should be something similar to this:

byte 0: BREAK char (as attention)
byte 1: Byte Count (how many bytes follows)
byte 2: Device address (from 0 to 8)
byte 3: Command Code (in theory should be from 0x01 to 0x80)
byte 4: The data starts here
byte n: The data ends here

Cool, but since I don't know anything about BFE commands (every device and company uses different ones) it's a great challenge.
I would ask if someone have a operating manual from BFE regarding this BD51-LC/Z2 or anithing that expose command codes, will be useful in the near future to allow us to use this equipment (that was amazing expensive in the past) and now you can find very cheap.

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