Gewiss, Intercom System, models:

CHORUS VELIA GW19216BK	User Manual
Chorus ANTAS GW19061	Programming Manual
Chorus Digital Vision	Technical Manual
Chorus KARALIS GW19011ME	Programming Manual
Chorus KARALIS GW19051ME	Programming Manual
Chorus KARALIS GW19137TG	Quick Start Manual
Chorus NAXOS GW19201BK	Installation Instructions Manual
GW19221BK	Installation Manual