Interoperability of analog voice switches and IP telephony systems

The SPC has a history of nearly a century, now China has many manufacturing types of enterprises are still using the SPC, which is what we want to say the analog voice switch.

When customers find us looking for solutions, especially in the manufacturing industry, and they still have traditional switches, they ask us if we can get a new phone system and a traditional analog voice switch. The answer, of course, is yes. Next, we offer a docking scheme for IP telephony systems and analog switches for this topic.

There are two main methods of connection,
One is to connect analog voice switches via FXO and FXS, and the other is to connect analog voice switches via a digital relay E1 Gateway

(i) FXO and FXS connect analog voice switch
Let's look at a network topology diagram.

Next we introduce the gateways and devices that appear in the diagram

3CX system-The system is redeployed to the enterprise's existing TCP IP network. It will act as a new voice communication system for the enterprise.

IP Phone-it will act as a new telephone extension in the system due to the simple IP telephony and cabling. IP phones can be borrowed to an enterprise's existing TCP/IP network deployment, where only one network cable can be deployed on each card bit, and no additional phone lines need to be deployed. IP Phone has two network ports, one network port connected to the office of the Internet, another network port connected to the office of the computer. It is through this design that the enterprise in the use of the existing network of a cable to make telephone communications and computer office at the same time.

Analog Voice Switch-here we assume the original voice communication system for the enterprise. Any brand can be, the method of connection method is similar.

Analog telephones-the old-fashioned telephones used with analog switches.

FXO Voice Gateway-it connects to the 3CX system via TCP IP. His analog port will connect to the inside of the analog telephone switch. This scheme works by calling out all the extensions of the entire IP telephony system as an extension of the analog voice switch.

FXS Voice Gateway-he makes connections through TCP and 3CX systems. His analog port will connect to the outside interface of the analog telephone switch. In this scenario, the entire analog voice switch is called out as an extension of the IP telephony system.

After interpreting the system's various devices, we formally enter the topic.

3CX connects two voice gateways and IP telephones via TCP/IP. TCP/IP connections are limited to LAN connections, or XXX networks (public connections can cause voice quality instability.) This is not covered in the scope of this article). The IP Voice gateway has two voice gateways, one is the FXO Voice gateway and the other is the FXS Voice gateway. FXS is registered as an extension 701 below 3CX.

In the outbound route here, the 3CX outbound policy is set to 1XX for the extension to go out from the outside of FXO. You can directly reach the extension below the analog switch. The IP Voice gateway is comprised of two voice gateways. One is the FXO Voice gateway, and one is the FXS voice gateway. FXS is registered as an extension 701 below 3CX. The 3CX outbound policy is set to 1XX for the extension to go out from the outside of FXO. You can directly reach the extension below the analog switch.

A dialing method: IP Phone 101 can directly dial 301 analog phone. 301 will display 4XX (depending on the number of the Ext interface extension of the analog switch). Each call takes up a phone line in the analog switch. Release after the call is over.

B Dialing Method: Analog phone 302 by prefix 9+102 can dial IP phone 102. Analog ext. 301 When you call 102, the 102来 display will be 701 (depending on the number of the FXS ext extension) Each call will occupy a telephone line on the analog switch line. Release after the call is over

Explain the above two dialing methods. We can achieve 3CX below the extension can dial the analog voice switch below the extension. But some friends will ask, can only one device to complete the connection?
This is also possible. Only the extension below the analog voice switch cannot directly dial the extension below 3CX and must be dialed by two times. We use only one FXO gateway as an example.

C Dialing Method: You can also use only one FXO gateway to complete and simulate a voice switch connection. This connection method to make a call is: 1. Analog telephone 301 Call the analog switch extension 401, hear a two-time dial tone, and then dial IP extension 101.

Note -3CX The following extensions and analog switches have little interconnection problems. But there may be some problems.
1. Analog ext. 301 When you call 101, the 101来 display will be 701 (depending on the number of FXS ext extension) IP Ext 101 calls 301, 301 will display 4XX (depending on the analog switch's ext.
2. Because the analog switch is older equipment, and IP PBX interoperability may produce voice quality issues. There is a small probability that this problem will arise. If 3CX is deployed in the cloud. Poor quality of the network will also be the possibility of increasing the noise.
3. Analog switch because of the time, interconnection and interoperability problems. This can make it possible for integrators to generate multiple home costs. Sometimes a hardware failure occurs in the analog voice switch. 3CX and analog Voice switch interconnection there will be problems.

(ii) Digital relay E1 Gateway Connection Analog Voice switch
This connection must be made to allow the analog voice switch to have enough digital E1 interfaces. To make it easier for everyone to understand, let's take a look at the topology diagram first.

The main fxo/and FXS gateways are replaced with E1 gateways.

After the introduction of the above Fxo and FXS. You should have a general understanding of the interconnection of IP telephony systems and analog voice switches. Do not use the author here too much to repeat.
After the physical connection is done. As long as the administrator of the 3CX and the administrator of the analog voice switch make the call and outbound routing, they can complete the interconnection and interoperability of the analog voice switch and the 3CX under the extension.
The advantage of the E1 interface is that 1 can provide better voice quality than a copper connection, 2. It is also normal to have a caller ID; 3. There is no bite-line problem in the communication. The disadvantage is that not many analog voice switches can provide the E1 interface.

Here, we have introduced the analog voice switch and IP telephony system 3CX under the extension of each other. Thank you for your attention.

Interoperability of analog voice switches and IP telephony systems