# 13430: Play: Invalid DTMF String

Log Type: APPLICATION

Log Level: WARNING

## Description

The `digit` attribute may contain numbers, the `#` and `*` characters, the letters `A`, `B`, `C`, `D`, as well as lowercase `w` to "wait" for half a second or uppercase `W` to "wait" for a full second.

### Possible causes

The attribute `digit` includes an invalid character.

### Possible solutions

Ensure the `digit` attribute only contains the characters: `0123456789ABCD*#wW`.