A TPIN is a 4-digit Telephone Personal Identification Number used to verify the authenticity of the customer to enable them to perform various functionalities over the phone, such as placing orders or accessing call and trade facilities. It is a unique code for each account and is a secured service. The TPIN is sent to the customers registered mobile number and email ID by the Central Depository Services Limited (CDSL) . The TPIN is also used by some trading platforms, such as Upstox, to authenticate users over the phone for faster service for Call and Trade. The TPIN is generally numeric and can range from 1000 to 9999.