????

The link you supplied to the 'GISO GB LAN/AES/EBU isolation for studio use' states it can be used for either LAN usage (that's how the internal transformers would be wired for) or with adapters to use the transformers for AES/EBU.

The adapters are required since the isolator should be designed (internally connected) for LAN usage (i.e. 1000Base-T) and you are trying to use it for something else.

The isolator is for LAN use - the isolator has RJ45 sockets - with adapters to get the signals across the transformer winding you can use it for other things.

SpeakerLink also uses RJ45 BUT:
SpeakerLink is not carrying the same signals as a LAN cable (let alone on the same pins).
SpeakerLink is NOT just AES/EBU (actually it isn't AES/EBU).

SpeakerLink is:

- DC Power
- Meridian Digital Audio - MHR or SPDIF over 'AES/EBU type' - -- Balanced connection
- Meridian Master Comms
- Meridian Slave Comms
- RS232 Transmit
- RS232 Receive
Not including power there is the equivalent of 5 pairs of signals (SpeakerLink is sharing grounds between Meridian Comms / RS232 - hence only 8 wires/pins instead of 10.)

A transformer works with coils - i.e. pairs of signals - how does 5 pairs go through 4 transformers?

Look at the pinouts in the SpeakerLink used as Digital Out (XLR or SPDIF) thread.

How would sending RS232 RX + TX into the same transformer work?

If it actually works - surely that means it's not actually isolating?

If you only want Digital Audio - that isolator might work - assuming you cut out the other pins to avoid the chance of wrecking the kit at either end (most people using SpeakerLink want the comms and also don't treat the electronics at either end as disposable for experimentation).

Wiring inductors (transformer coils) across comms signals might be interesting, but take the example of a spark plug - do you really want to risk your speakers / source having the comms interface / RS232 interface fried? (Whether through back-EMF, connecting the DC power across a coil, etc...)

If you are trying to isolate SpeakerLink properly - you would need opto-isolators for the RS232 to make sure the levels end up correct - and possibly the same for Meridian Comms (but I've not looked at the Comms signal format).

Looking around at what's got RJ45 within reach of me that is not wired the same as a LAN port (and will possibly give expensive results if mistaken for one):

Meridian SpeakerLink - RJ45
Allen Bradley Powermonitor 3000 display - RJ45
Allen Bradley DH485 - RJ45
Allen Bradley ControlNet - RJ45
Cisco Console port RS232 - RJ45
Red Lion Data Station RS485 - RJ45

RJ45 doesn't mean LAN signals.

I would appreciate corrections to any of this.

Without Meridian's endorsement - personally I would not risk any kit by connecting an isolator designed and wired for LAN usage. (inductors can give back more volts than goes in and RS232 is meant to use specific DC levels).

If it works - RS232 probably won't (don't the newer speakers make use of that?)

It could turn out to be an expensive mistake.

Matt.

Last edited by Carl; 2014-08-06 01:49. Reason: URL Wrapped with URL Tag and description.