The two types of Client database are the Local and Master client databases. The Main Client Database is used only by MonTel for Windows and is stored on the file server. It contains the client, contact, employee, more detailed Call Records, and other information in a heavily normalised database for maximum utilisation of space and integrity of data.
The Local Client Database is used only by MonTel for windows, and must be stored on the hard drive of the user's computer. This database contains links and Structured Query Language (SQL) instructions for fast retrieval of data from the Main Client Database.
Unlike the Call record databases, these databases are linked to each other. The Master Client Database is created by and used by the MonTel Client, and is generally located in the CLIENTDB sub-directory of the MonTel Data Directory on the file server. It is not used at all by the MonTel Server. The Master Client Database is a fully implemented relational database, using the Microsoft Jet engine, the same power house as Access 97 (in the MonTel 32bit version). The Local Client Database is also a "Jet" database, though most tables are just linked (or referred) back to the Master Client Database. It is present so that queries, temporary tables and results are stored locally rather than over the network. This reduces network traffic, and makes MonTel faster.
Note that Client data is just part of the information stored in a client database. The two terms should not be confused.