Hierarchy of the sectors:
In every group there is a master sector, indicated with underlined fonts in the list below. The master sector takes care of every other sectors task inside its group, in case those have not been opened yet.

Opening sectors:
Under any circumstance, the master sector has to be opened first, followed by the other ones according to their description in the order stated above. A rule of thumb is that (except for Budapest Director and Budapest Apron) the other secondary sectors are only allowed to be opened during events and in case of extremely high traffic with the approval of HU-AOC/AOAC or HU-DIR/ADIR.

Area Control Centre (ACC) group

FSD ID Frequency IVAC2 Callsign FRA
LHCC_E1L_CTR 120.375 E1L Budapest Radar ADC
LHCC_W1L_CTR 133.200 W1L Budapest Radar APC
LHCC_E3U_CTR 135.555 E3U Budapest Radar ACC
LHCC_W3U_CTR 132.055 W3U Budapest Radar ACC

In case of a lateral sectorization the online sectors have to be the lowers (E1L and W1L). E1L and E3U must be online when vertical sectorization is in use. Mixed sectorization (both lateral and vertical) is also allowed. In this case the sector names are perspicuous.

Flight Information Centre (FIC)

FSD ID Frequency IVAC2 Callsign FRA
LHCC_EI_FSS 133.000 FIC-E Budapest Information ADC
LHCC_WI_FSS 125.500 FIC-W Budapest Information APC
LHCC_NI_FSS 119.350 FIC-N Budapest Information APC

The sector boundary line is the River Danube, EI manages the eastern and WI the western side below 9500 feet, except for the uncontrolled airspaces below Budapest TMA which is managed by NI.

Budapest - LHBP

FSD ID Frequency IVAC2 Callsign FRA
LHBP_TWR 118.100 BP AD Budapest Tower AS3
LHBP_G_GND 121.900 BP GRC Budapest Ground AS3
LHBP_A_GND 122.450 BP A GRC Budapest Apron ADC
LHBP_DEL 134.550 BP CDC Budapest Delivery ADC
LHBP_E_APP 122.975 APPE Budapest Approach ADC
LHBP_W_APP 129.700 APPW Budapest Approach APC
LHBP_D_APP 119.500 TD Budapest Director APC

Regional airports

Only flight information service is provided on the mentioned aerodromes. Opening facility on other airfields is not allowed as both on IVAO and in real life there is no significant traffic. 

FSD ID Frequency IVAC2 Callsign FRA
LHSM_I_TWR 134.575 SM Balaton Info AS1
LHDC_I_TWR 125.900 DC Debrecen Info AS1
LHPR_I_TWR 129.900 PR Pér Info AS1
LHPP_I_TWR 126.905 PP Pogány Info AS1