Mode S vs Mode A

[moilethon]

Bonjour,
I work in the simulation field and I have a question on Mode S transponder.
Can an aircraft equipped with mode S transponder be transmitting just the aircraft callsign (id) without the altitude readout (no Mode C).
Thank you.

[Intercepted]

Yes, the transponder normally has the modes STB, ON and ALT

STB The transponder is on, but will not reply to any interrogations.

ON The transponder will respond to all interrogations, but altitude
reporting is suppressed.

ALT The transponder will respond to all interrogations.

The same goes for both Mode C and S transponers.