To launch VoIP-based telephony systems we use several equipment and devices. For each method of VoIP implementation we use one or more of these devices. Below you get familiar with the equipment, devices and their functions.
PBX (Private Branch Exchange) is a private call center for wiring telephone system inside companies. It will be installed in a complex and within it extensions can have telephony conversation with each other.
IP-PBX is a PBX using network platform which is connected to network switch. IP Phones, software, mobile and other devices connected to the network will register to IP-PBX. As for registration there is no need to a physical cable directly to call center geographical limitation disappears and each device is sufficient somehow connected to the network that can be accessed via LAN or wireless intranet and the Internet.
IP-PBXs are available in two hardware and software models. In software model, we install software and special cards on the server and after configuration server act as PBX. In hardware model manufacturers produce modular boards for FXO/FXS cards and install their own software on it.
What is FXO and FXS?
FXO (Foreign Exchange Office) convert analog dial tone to VoIP signal
FXS (Foreign Exchange Station) convert received VoIP signal to analog dial tone
VoIP gateways are devices which convert analog voice and fax to VoIP and vice versa. These devices based on the number of entries has RJ11 socket for analog and E1 / T1 and Ethernet port for network connectivity and in FXO, FXS, E1 / T1 models are available. Two methods can be used device within the VoIP gateway.
Transmission line: we use this method to transfer analog city line or internal PBX telephone dial tone from one point to another. We put FXO device and connect urban lines to it. On the second point, we install FXS device and connect analog phones to it. After setting two phones connected to FXS FXO device connected to the receiving dial tones.
Connect to IP-PBX: to communicate between city lines and analog telephone. Urban lines connect to FXO ports and analog phones and fax devices connected to FXS devices. Then with related settings in the FXO, FXS and IP-PBX all extension can use city lines and connect each other.
Software IP-PBXs are not able to use analog city lines, phone and fax. To solve this problem we use special FXO/FXS cards. VoIP cards are produces in PCI/PCIe format with FXO/FXS modules which can connect to analog line, E1 and devices.
IP phones act like analog phone but work with IP-PBX. These phone have one or two LAN port which act as bridge and you don’t need two network cable for both computer and phone. IP-Phones need electricity to work and for this matter we can use adaptor or POE switch which send the power through network cable. There is also USB phone which connect to computers.
IP-Phones needs electricity to power on. One way is using adaptor beside each phone but there is a better way and this is using POE switch. POE technology send electricity through two idle wire to power on devices who needs power such as IP-Phones, Cameras and wireless devices. There is a standard called 802.11f. All devices which support this standard can be powered on with POE switches. Benefit of using POE switch are you don’t need one adaptor and power wiring beside each phone and you can use ups for the switch so at the time of power outage phone still work.
Softphones are software which simulate phone devices on computer/mobile devices and you can use them as phone and you can use with headphone or speaker to have conversation.
ATA (Analog Telephone Adaptor) convert phone to IP-phone. This devices act like FXS gateway and produces in ½ ports in small sizes and don’t work with FXO devices but directly register in IP-PBXs.