will also affect the decoding time. Engineered systems often use tones in the 127.3 Hz to 162.2 Hz range to balance fast decoding with keeping the tones out of the audible part of the receive audio. Most amateur radio repeater controller manufacturers offer an audio delay option—this delays the repeated speech audio for a selectable number of milliseconds before it is retransmitted. During this fixed delay period (the amount of which is adjusted during installation, then locked down), the CTCSS decoder has enough time to recognize the right tone. This way the problem with lost syllables at the beginning of a transmission can be overcome without having to use higher frequency tones. In early systems, it was common to avoid the use of adjacent tones. On channels where every available tone is not in use, this is good engineering practice. For example, an ideal would be to avoid using 97.4 Hz and 100.0 Hz on the same channel. The tones are so close that some decoders may periodically false trigger. The user occasionally hears a syllable or two of co-channel users on a different CTCSS tone talking. As electronic components age, or through production variances, some radios in a system may be better than others at rejecting nearby tone frequencies. Digital-Coded Squelch CTCSS is an analog system. A later Digital-Coded Squelch (DCS) system was developed by Motorola under the trademarked name Digital Private Line (DPL). General Electric responded with the same system under the name of Digital Channel Guard (DCG). The generic name is CDCSS (Continuous Digital-Coded Squelch System). The use of digital squelch on a channel that has existing tone squelch users precludes the use of the 131.8 and 136.5 Hz tones as the digital bit rate is 134.4 bits per second and the decoders set to those two tones will sense an intermittent signal (referred to in the two-way radio field as "falsing" the decoder). List of tones CTCSS tones are standardized by the EIA/TIA. The full list of the tones can be found in their original standard RS-220A, and the most recent EIA/TIA-603-E; the CTCSS tones also may be listed in manufacturers instruction, maintenance or operational manuals. Some systems use non-standard tones. The NATO Military radios use 150.0 Hz, and this can be found in the user manuals for the radios. Some areas do not use certain tones. For example, the tone of 100.0 Hz is avoided