So I have been trying to learn me something about the CAN system on the LR3, but I am no expert, and I am little confused about the Medium Speed...

From wikipedia I have this about high speed CAN - "ISO 11898-2, also called high speed CAN, uses a linear bus terminated at each end with 120 Ω resistors"

That lines up with the LR3, but wikipedia only references low-speed CAN "ISO 11898-3, also called low speed or fault tolerant CAN, uses a linear bus, star bus or multiple star buses connected by a linear bus and is terminated at each node by a fraction of the overall termination resistance. The overall termination resistance should be about 100 Ω, but not less than 100 Ω."

Land rover documents I have read about the CAN bus mention that some control modules are connected using a 'spur' connection, which to me suggests low speed CAN, but I can't find which modules are connected in a spur configuration.

CAN Buses are standardized systems mandated by OBDII. So I don't think land rover has much wiggle room in deviation. My question is basically this; is the medium speed CAN a high speed or low speed CAN? Oh and does anyone know which modules are 'spur' connected?

 

What I want to know is - what are you planning to do with this knowledge? Because I suspect you have something specific in mind.

 

This is more of a fact finding exercise for now, I am trying to understand the operation of the computer system, so I can troubleshoot it when I have problems

 

Ms-can is a ford proprietary can bus. None of the items on it are safety or emissions related, so they don't have to meet the obdii standards.

 

I found a reference to baud speed in one of the LR3 manuals. With the MS being lower. I am of the belief that both are 'High-speed' as per OBD standardization, but the network baud rates are different

 

You might try asking GAP for specs, they've been working with the interface for some time now so I imagine they've got a great handle on how it works.

 

Isn't a large portion of the system based around fiber-optics? Or possible just the audio out of the DVD-amp which is TOSLINK but I thought most of the entertainment was fiber? Not sure if that helps at all.

 

The MOSTbus is fiber optic.

 

I'm getting old. This sort of talk makes me long for the old days when all you needed was 12v plus some fuel and you were in business.

I'm becoming a dinosaur.

Of course, I know Volkov is trying to go even simpler than that on his 101 and do away with even the need for 12v. Though I want to see him pump up that air starter by hand - I'll be sure to have a cold beer waiting in my 12v fridge for once he's done.

 

Pumping up my air starter tanks by hand is a last resort option. If I don't have a compressor, and can't push start the truck, i have a plan C

Redundancy is a good thing, you can say that again