We use Cisco 8861 desk phones. When a call is on hold after pressing the transfer option, if you decide to use the Contacts button to search for a contact, you must press that button, pick what directory to search, enter in your search parameters, press the search button, wait for the results then choose the result you want and press call all within 12 seconds. If you fail to do all of that you get a timeout message and at that point you have to cancel the contact search and resume the call and then try it again and see if you can speed through the process in less than 12 seconds. Half the time the timeout is happening when the search is occurring.
This is not practical in any manner so having the option to extend the timeout would be useful.