dialable

Dialable describes strings or inputs that can be entered into a dialing interface to initiate a phone call. In telephony, this means a sequence that a user can press on a keypad to reach a destination. Dialable numbers typically consist of the digits 0 through 9 and may include the star (*) and hash (#) keys for service codes or special functions. For international dialing, a leading plus sign (+) is commonly supported on modern devices and is considered dialable in many contexts. Non-digit punctuation such as spaces, parentheses, or hyphens may appear in written form but is usually ignored by the dialing system when processing the input.

In practice, software and systems often treat dialable input as the subset of a string that can be converted into a usable telephone number after normalization. This usually involves stripping formatting and converting to a canonical form, such as the international E.164 digit sequence, while preserving or indicating international or national prefixes as appropriate. The concept is central to address validation, contact management, and call routing.

Standards and formats related to dialable numbers include the tel URI scheme, which represents dialable numbers for initiating calls from software and devices. International dialing formats commonly rely on the plus prefix to denote international access, with subsequent digits forming the dialable number. The exact set of characters considered dialable can vary by device, country, and network, so implementations typically include validation against a dialing plan.

---