Length and format validation cases
Test minimum and maximum lengths, invalid characters, whitespace handling, punctuation removal, and copy-paste behavior across every identifier field.
These checks catch the most common user-input problems before they become ticket volume or data-cleanup work.
Normalization and display cases
QA should confirm whether input is stored raw or normalized, whether display masks sensitive values, and whether exported data remains consistent across interfaces and APIs.
This matters for E.164 phone numbers, IMEI formatting, and identifiers that should retain leading digits without accidental truncation.
Error-state and support guidance cases
Good telecom forms need clear, specific errors such as wrong length, invalid check digit, or unsupported format rather than generic validation failures.
Support teams benefit when QA verifies that errors are actionable and consistent across both web and mobile workflows.