Modat features are programmable and could be used in any combination desired by the user. For example, some systems use only push-to-talk unit ID or only emergency button. Others may use both. One setting that is adjustable is the length of time from push-to-talk press until the tone sequence starts. This delays the start of the tone sequence to allows systems with long time constants in CTCSS decoders or voting comparators to open an audio path. In addition to Motorola, other companies make add-on encoders that can modify a different brand of radio to work with a Modat system.