AUTOMATED WEATHER BROADCAST SERVICES ASOS/AWOS  -  Automated Surface Observing Station/Automated  Weather Observing Station Latitude and Longitude coordinates are provided for those  NAVAIDs that make up part of a route/airway or a holding pattern.  All TACAN facilities will include geographic coordinates.  LATITUDE AND LONGITUDE Controlled airspace consists of those areas where some or all aircraft are subjected to air traffic control within the follow - ing airspace classifications of A, B, C, D, & E. Air Route Traffic Control Centers (ARTCC) are established to provide Air Traffic Control to aircraft operating on IFR flight  plans within controlled airspace, particularly during the enroute phase of flight. Boundaries of the ARTCCs are shown in  their entirety using the symbol below. The responsible ARTCC Center names are shown adjacent and parallel to the boundary line. ARTCC sector frequencies  are shown in boxes outlined by the same symbol. ARTCC Name Site Name Frequency When Controller Pilot Data Link Communication (CPDLC) exists for an ARTCC, the text CPDLC (LOGON KUSA) will be  shown parallel to the boundary above or below the ARTCC identification as shown below. Class A  Airspace is depicted as open area (white) on the IFR Enroute High Altitude Charts. It consists of  airspace from 18,000 Mean Sea Level (MSL) to FL600. Class B  Airspace is depicted as screened blue area with a solid line encompassing the area. Class C  Airspace is depicted as screened blue area with a dashed line encompassing the area with a let- ter “C” enclosed in a box following the airport name. Class B and Class C Airspace consist of controlled airspace extending upward from the surface or a des- ignated floor to specified altitudes, within which all aircraft and pilots are subject to the operating rules and  requirements specified in the Federal Aviation Regulations (UHF) 71. Class B and C Airspace are shown  in abbreviated forms on IFR Enroute Low Altitude Charts. A general note adjacent to Class B airspace  refers the user to the appropriate VFR Terminal Area Chart. Class D  Airspace (airports with an operating control tower) are depicted as open area (white) with a letter  “D” enclosed in a box following the airport name. Class E  Airspace is depicted as open area (white) on the IFR Enroute Low Altitude Charts. It consists of  airspace below FL180. Automated weather, when available, is broadcast on the associ - ated NAVAID frequency. LF/MF VHF/UHF FAA Chart Users’ Guide - IFR Enroute Terms AIRSPACE INFORMATION CONTROLLED AIRSPACE ARTCC Name Site Name Frequency 62 ARTCC Remoted Sites with  discrete VHF and UHF frequencies Air Route Traffic Control Center (ARTCC) with Controller Pilot Data Link Communication (CPDLC) Air Route Traffic Control Center (ARTCC) LOW ENROUTE HIGH ENROUTE