Electrical designations and abbreviations

Hello everyone

I am currently going through the construction and service description, but there are some terms and abbreviations that I do not understand. I would be grateful if someone could explain these things to me, as I have little experience with electrical installations in German houses (and my German is not yet good enough):
- Per staircase: 1 x cross-switch with 1 x DL, 1 x WL and 4 switches
Why is a cross-switch installed per staircase? Is it common to control all staircase lights simultaneously from each floor? And is this usually independent of the lighting in the hallways?
What are WL & DL? And why do I need 4 switches per staircase?

- Per basement room: 1 x off-switch with 1 x DL
What is meant here by this off-switch with DL?
Note: This DL is only used in basement rooms and the technical room.

- Hallway: 2 x off-switch with 1 x WL
What is meant here by this off-switch with WL?
Note: This WL is only used in basement and ground floor hallways and the house entrance.

These 2 switches should also be changeover switches, right?

- Living area (and in all other rooms): off-switch
How does this switch differ from other switches with WL or DL?

Kind regards
Thank you very much

Without guarantee:
DL-> ceiling light, WL-> wall light

Crossover switching on the stairs means that you can switch the lights both at the top and bottom of the stairs.
There are 4 switches because: 1x wall light at the bottom, 1x ceiling light at the bottom, 1x wall light at the top, 1x ceiling light at the top

I think a single switch is a normal circuit. How this is supposed to work with two switches without a two-way switch is not clear to me. ;-)

The others are just normal switches.

A four-way switch circuit with 4 switches, that is 2 two-way switches and 2 four-way switches, is basically never built. You should directly use a push-button switch circuit. Basically, the staircase should be wired separately from the hallway or foyer lighting. However, you won’t be happy with a single-pole switch in the hallway or foyer either. During the sampling phase, an extra charge for at least a two-way or four-way switch is pre-programmed.

There are 4 switches simply because: 1x downstairs wall light, 1x downstairs ceiling light, 1x upstairs wall light, 1x upstairs ceiling light

That sounds logical, but no wall outlet is mentioned in the specifications (only a ceiling outlet).

You usually don’t build a cross circuit with 4 switches, meaning 2 toggle switches and 2 cross switches at all. You should directly use a push-button circuit.

That’s true, the push-button circuit is much simpler. It’s not quite clear how they want to install 4 switches for a single staircase lamp!

Basically, the staircase should be switched separately from the hallway or foyer lighting.

That makes sense.

I think a simple on/off circuit is a normal circuit. How that should work with two switches without a toggle switch is not clear to me. ;-)

But with a simple on/off circuit in the hallway or foyer you won’t be happy either. At the sample selection there is at least an extra charge for a toggle switch or cross circuit.

Yes, we need a toggle or cross circuit. They write 2 (and in some cases 3) switches. Maybe it’s just a general term, since it always controls only 1 ceiling outlet.

Thank you very much. The situation is now clearer, and I can continue talking with them :)