This post is part of Getting On The Air: Modes, Operations, and Making Contacts.
RepeaterBook and ARRL TravelPlus are the two directories most hams end up using, and both pack a lot of information into a small number of columns that are not always self-explanatory to a newer operator.
Frequency and Offset
The listed frequency is usually the output, what you receive on, with the offset (plus or minus, and how much) telling you where your transmit frequency actually falls. A plus offset on 2 meters typically means 600 kHz up from the listed frequency, minus means 600 kHz down, though always check the actual value listed rather than assuming the band-standard offset applies.
PL, DPL, and Tone Columns
PL (sometimes shown as CTCSS) is a sub-audible analog tone your radio needs to transmit to access the repeater. DPL or DCS is the digital equivalent. Some listings show separate uplink and downlink tones, meaning what you need to transmit differs from what the repeater sends back, program both correctly or you will hear nothing even though your transmission is being repeated.
Status and Use Codes
Listings often flag a repeater as open, closed, or club-use-only, and separately note whether it is linked to a wider network like EchoLink, AllStarLink, or a statewide system. A closed repeater technically requires club membership or specific authorization to use, worth checking before you assume every repeater on the list is fair game.