RADIO AIDS TO NAVIGATION All IFR radio NAVAIDs that have been flight checked and are operational are shown on all IFR Enroute Charts. Very High  Frequency/Ultrahigh Frequency (VHF/UHF) NAVAIDs, Very high frequency Omnidirectional Radio range (VORs), Tactical  Air Navigation (TACANs) are shown in black, and Low Frequency/Medium Frequency (LF/MF) NAVAIDs, (Compass Loca- tors and Aeronautical or Marine NDBs) are shown in brown. On IFR Enroute Charts, information about NAVAIDs is boxed as illustrated below. To avoid duplication of data, when two  or more NAVAIDs in a general area have the same name, the name is usually printed only once inside an identification  box with the frequencies, TACAN channel numbers, identification letters, or Morse Code Identifications of the different  NAVAIDs are shown in appropriate colors. NAVAIDs in a shutdown status have the frequency and channel number crosshatched. Use of the NAVAID status "shut- down" is only used when a facility has been decommissioned but cannot be published as such because of pending  airspace actions. FAA Chart Users’ Guide - IFR Enroute Terms 61 NAVIGATION AND COMMUNICATION BOXES - COMMON ELEMENTS LOW ENROUTE CHARTS RCO Frequencies  NAVAID Name FREQ, Ident, CH, Morse Code Latitude, Longitude Controlling FSS Name HIGH ENROUTE CHARTS RCO Frequencies  NAVAID Name Frequency, Ident, Channel, Latitude, Longitude Controlling FSS Name COMMON ELEMENTS (HIGH AND LOW CHARTS) RCO FREQUENCY  Single Frequency Multiple Frequencies  Frequencies transmit and receive except those followed by R and  T: R - Receive Only T - Transmit Only  NAVAID BOX Thin line NAVAID boxes without frequency(s) and FSS radio  name indicates no FSS frequencies available. Shadow NAVAID box indicates NAVAID and Flight Service Sta - tion (FSS) have same name. VHF/UHF LF/MF  FREQUENCY PROTECTION Frequency Protection usable range at 18,000’ AGL - 40 NM Frequency Protection usable range at 12,000’ AGL - 25 NM (L)  (T) DISTANCE MEASURING EQUIPMENT Facilities that operate in the “Y” mode for DME reception (Y) VOICE COMMUNICATIONS VIA NAVAID Voice Transmitted No Voice Transmitted NAVAID SHUTDOWN STATUS  VHF/UHF LF/MF PART TIME OR ON-REQUEST VHF/UHF LF/MF