# 21206: Invalid SendDigits

Log Type: APPLICATION

Log Level: ERROR

## Description

You attempted to initiate an outbound phone call, and you included a `SendDigits` parameter that wasn't valid. `SendDigits` is optional, and specifies that Twilio should simulate sending keypad digits when the party answers. `SendDigits` 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 parameter `SendDigits` includes an invalid character.

### Possible solutions

Ensure the `SendDigits` parameter only contains the characters: `0123456789ABCD*#wW`.