CTCSS stands for continuous tone coded squelch system, often referred to as "PL" (Motorola's trade name). Many repeaters require the use of a PL tone to access the repeater.

Contrary to popular belief, the requirement of a PL tone to access a repeater does NOT mean it is closed. PL is frequently used to preclude nuisance kerchunks in high RF environments as well as helping solve interference problems. Some repeaters may also generate a PL tone on the repeater output so that repeater users who are equipped with a radio capable of decoding PL will not hear other interference sources on the channel that would otherwise open the squelch on the user's radio.

It is up to the owner / trustee of the repeater to decide whether or not to make public the PL tone for a particular repeater. T-MARC follows the wishes of the owner / trustee in publishing the PL code only when so requested.

T-MARC strongly recommends the use of PL on repeaters' receivers. PL is a minor inconvenience when you consider how many potential problems it can eliminate. The use of PL may be required for a coordination to be granted if conditions so warrant, such as proximity to a co-channel repeater, or in an area where band openings frequently aggravate co-channel interference problems.

T-MARC will soon publish a PL tone plan in the hopes that repeater owners / trustees in a given area will standardize on a particular PL tone and incorporate it into their operational plans. The reason for this plan is to make it easier for users to operate the local repeaters in an area, as some older radios are only capable of a single PL tone as compared to modern radios which can have PL tones selected on a per-channel basis.

You can assist your users in getting PL boards for their radios. Ask any 2-way shop and they will most likely recommend COMSPEC. That translates to: Communications Specialists 426 W Taft Ave,Orange, CA 92665-4296 Phone: (714)998-3021. They can provide boards for a modest sum that will fit inside most radios including handhelds. That's one possible source, there must be others. I'm not advertising for anyone, only suggesting a possible source to get you started looking in the right direction.

Following is a chart showing each PL tone's two-character alphanumeric designator and the corresponding tone frequency in Hertz.

Code Tone Freq.   Code Tone Freq.   Code Tone Freq.
XZ 67.0   1B 107.2   6A 173.8
WZ 69.3   2Z 110.9   6B 179.9
XA 71.9   2A 114.8   7Z 186.2
WA 74.4   2B 118.8   7A 192.8
XB 77.0   3Z 123.0   M1 203.5
WB 79.7   3A 127.3   8Z 206.5
YZ 82.5   3B 131.8   M2 210.7
YA 85.4   4Z 136.5   M3 218.1
YB 88.5   4A 141.3   M4 225.7
ZZ 91.5   4B 146.2   9Z 229.1
ZA 94.8   5Z 151.4   M5 233.6
ZB 97.4   5A 156.7   M6 241.8
1Z 100.0   5B 162.2   M7 250.3
1A 103.5   6Z 167.9   0Z 254.1

T-MARC thanks ARCC for the use of the basic page with our modifications.