The closest document that I'm aware of is the features and services guide:
Desktop Call Pickup
User can perform desktop call pickup on in-progress mobility calls either by hanging up the call on the mobile phone or by putting the mobility call on hold with the midcall hold feature. When hanging up or ending the call at the mobile phone, the user can then resume the call on the desk phone within 10 seconds (default). When the remote destination hangs up, Cisco Unified Communications Manager puts the associated desk phone in Hold state, which allows the user to resume the call by pressing the Resume softkey. The Maximum Wait Time for Desk Pickup setting on the End User Configuration window determines the amount of time the call remains on hold after the hang-up at the remote destination. The default specifies 10000 milliseconds (10 seconds).
Alternatively, the user can also perform desktop call pickup by placing the call on the mobile phone on enterprise hold with the midcall hold feature (*81) and then resuming the call on the desk phone. When Cisco Unified Communications Manager receives the *81, Cisco Unified Communications Manager places the associated desk phone in a Hold state so the user can resume the call. Note that with this method, the Maximum Wait Time for Desk Pickup timer does not apply to the hold state and the call gets held indefinitely until the user resumes the call.
Please remember to rate helpful responses and identify helpful or correct answers.
