https://help.tallysolutions.com/docs/te9rel64/sync/Synchronisation_Via_Tally.NET.htm

Synchronisation Via Tally.NET Server

When online synchronisation is performed using Tally.NET Server, the Tally.NET Server acts as a bridge or a connection between the server and the client company.

To know more, click the following links:

Configuring Client/Server

Configuring TSS Features

Connecting Server Company to Tally.NET Server

Creating Sync Rule on Client

Activating Sync Rule on Server

Synchronising Data