1. Dial a number When you dial a phone number, your phone sends a signal to the local exchange, known as the central office (CO). This signal includes the digits of the number you called. 2. Local iran mobile phone numbers database exchange The local exchange is the initial point of contact in the PSTN. It receives the dialed digits and determines . If you make a local call, the local exchange will connect your call directly to the recipient's phone line. 3. Tandem offices If you make a long distance call, the local exchange routes your call to the gateway.
The gateway routes your call to the appropriate long distance network. 4. Toll booth The gateway transfers your call to a toll office for long distance or international calls. Tollbooths manage the routing of long-distance calls. 5. International portal For international calls, the toll booth will route your call to an international gateway. It handles the translation of your calls from domestic to international networks, connecting you to recipients in other countries. 6. Operator access point Carrier access points are checkpoints within the network that manage data flow and prevent network congestion.
