Yeah, the AFD didn't have the answer, that was where I was looking when I got stumped.
From the AFD legend's discussion of Communications (duh):
"Civil Communications Frequencies—Civil communications frequencies used in the FSS air/ground system are now operated
simplex on 122.0, 122.2, 122.3, 122.4, 122.6, 123.6; emergency 121.5; plus receive-only on 122.05, 122.1, 122.15, and
123.6.
a. 122.0 is assigned as the Enroute Flight Advisory Service channel at selected FSS’s.
b. 122.2 is assigned to most FSS’s as a common enroute simplex service.
c. 123.6 is assigned as the airport advisory channel at non-tower FSS locations, however, it is still in commission at
some FSS’s collocated with towers to provide part time Local Airport Advisory Service.
d. 122.1 is the primary receive-only frequency at VOR’s. 122.05, 122.15 and 123.6 are assigned at selected VOR’s
meeting certain criteria.
e. Some FSS’s are assigned 50 kHz channels for simplex operation in the 122-123 MHz band (e.g. 122.35). Pilots
using the FSS A/G system should refer to this directory or appropriate charts to determine frequencies available at
the FSS or remoted facility through which they wish to communicate.
Emergency frequency 121.5 and 243.0 are available at all Flight Service Stations, Towers, Approach Control and RADAR
facilities, unless indicated as not available.
Frequencies published followed by the letter ‘‘T’’ or ‘‘R’’, indicate that the facility will only transmit or receive respectively on
that frequency. All radio aids to navigation frequencies are transmit only."
Bob Gardner