:original_name: waf_02_0086.html .. _waf_02_0086: Character Set Specifications ============================ - Character Set Specifications for Key The key cannot be left blank or be an empty string. - In Deutsche Telekom, a tag key can contain uppercase letters, lowercase letters, digits, hyphens (-), underscores (_), and sign @. - In other environments, a tag key cannot contain the following characters: ASCII (0-31), equal signs (=), asterisks (*), left angle brackets (<), right angle brackets (>), backslashes (\\), commas (,), vertical bars (|), and slashes (/). - Character Set Specifications for Value The value cannot be left blank but can be an empty string. - In Deutsche Telekom, a tag value can contain uppercase letters, lowercase letters, digits, hyphens (-), and underscores (_). - In other environments, a tag value cannot contain the following characters: ASCII (0-31), equal signs (=), asterisks (*), left angle brackets (<), right angle brackets (>), backslashes (\\), commas (,), vertical bars (|), and slashes (/).