Coline Roux (asker) Mar 28, 2013:

Thanks Tony Thanks for your explanation, it's very clear!

Tony M Mar 28, 2013:

Yes you have! 'first-line service' means those minor tasks that can be performed by someone in the 'first line' — i.e. typically, the machine operator — without needing to call in the repair engineer.

This might be typically replenishing paper and changing toner cartridges for an office printer, or changing wiper blades and checking oil and water levels for a car.

Typically defined as things that don't need the use of tools...

So it seems that the organization here provides enough training for the customer to do their own first-line servicing, but is then available to take care of the second-line servicing if required.