There are 42 tones used for CTCSS, also known by Motorola as PL (Private Line?). I believe 38 of these are EIA standard; the others were added by Motorola. Most FRS radios have 38 tones, although some are now equipped with DCS as well. On most amateur radio equipment, the tone is set by frequency. FRS radios use a two digit number, from 00 to 38; on most brands, these numbers correspond to the same tones. Note that I say *most* brands - RTFM. GMRS radios may use a different numbering scheme, as they may support all of the EIA tones. A tone setting of 00 turns CTCSS off.
These are the tones and their designations.
FRS
Frequency Code Number
67.0 XZ 01
69.3 WZ --
71.9 XA 02
74.4 WA 03
77.0 XB 04
79.7 WB 05
82.5 YZ 06
85.4 YA 07
88.5 YB 08
91.5 ZZ 09
94.8 ZA 10
97.4 ZB 11
100.0 1Z 12
103.5 1A 13
107.2 1B 14
110.9 2Z 15
114.8 2A 16
118.8 2B 17
123.0 3Z 18
127.3 3A 19
131.8 3B 20
136.5 4Z 21
141.3 4A 22
146.2 4B 23
151.4 5Z 24
156.7 5A 25
162.2 5B 26
167.9 6Z 27
173.8 6A 28
179.9 6B 29
186.2 7Z 30
192.8 7A 31
203.5 M1 32
206.5 8Z --
210.7 M2 33
218.1 M3 34
225.7 M4 35
229.1 9Z --
233.5 M5 36
241.8 M6 37
250.3 M7 38
254.1 0Z --