In Salesforce there are a number of standard fields that usually get set if there's a CTI connector creating task/activity records. Fields involved include Call Type (CallType), Call Duration (CallDurationinSeconds), and Call Result (CallDisposition). If you look at the field-level security for those, it's Read-Only for every profile. That may seem to be a problem if you're testing functions that are based on them - say additional processing for Outbound call types - but you don't have access to a functioning CTI. Well, it's actually no problem at all. Those fields can still be set via code/API normally despite being Read-Only for all, which is probably just an UI only overlay to prevent end user editing.