When you want to connect your analog world to your IP Telephony infrastructure, the first thing that comes to your mind is an Analog Voice Gateway. In this article, let us look at how two popular 8-Port Analog Voice Gateways from Cisco Small Business (SPA 8000 & SPA 8800) can be put to use.
The basic thing you need to know about Analog Voice Gateways is that, they enable you to connect your analog telephony devices/ analog trunk lines to VOIP/ IP Telephony infrastructure. The components used in an IP Telephony system are IP PBX, IP Phones and accessories. But what if you already have a huge number of analog phones? You would naturally not want to replace all of them immediately with IP Phones. So, you can use the Analog Voice Gateways to connect Analog Phones, Fax Machines, Voice Paging devices and Analog Trunk Lines to your IP Telephony environment, both at the local branch and remote branches.
Cisco Small Business SPA 8000 has a total of 8 FXS Ports where you can connect up to 8 Analog Phones/ Fax machines etc.
Cisco Small Business SPA 8800 has a total of 4 FXS Ports (To connect Analog Phones/ Fax Machines) and 4 FXO Ports (To connect Analog Trunk Lines).
Both the above models also have a LAN port (actually two, the other one is used for configuring them) to connect to the IP Network. A common usage scenario for these 8 Port Analog Voice Gateways from Cisco is given in the below diagram.
In the above diagram, we have a head office above the Internet Cloud and a small branch below it. At the head office, there is an IP PBX (IP Telephony Server), IP Phones, Cisco Small Business SPA 8000 Analog Voice Gateway and SPA 8800 Analog Voice Gateway. IP PBX connects to the Internet/ ITSP to make VOIP calls and PSTN Trunks (through the 4 FXO ports of SPA 8800) to make local/national calls. The IP phones connect to the IP PBX through the LAN IP network (Network Switches and RJ-45 cables) and the analog phones connect to the IP PBX through the SPA 8000 Analog Voice Gateways (Up to 8 analog phones can directly terminate on the SPA 8000) and SPA 8800 (Up to 4 analog phones can directly terminate on the SPA 8800). Other than the analog phones, fax machines and voice paging (announcement) devices can also connect to the analog voice gateways.
All the phones (analog phones as well as IP phones) can dial out through the IP PBX & SPA 8800 for making VOIP calls through ITSP – Internet Telephony Service Provider & local calls through the analog trunk lines respectively.
At the small branch office, the analog phones/ fax machines can connect to a SPA 8000 (up to 8 of them) and the SPA 8000 is registered/ trunked with the IP PBX at the head office. So, through the Internet, any analog phone in the branch office can call any analog/ IP phone in the head office. If an SPA 8800 were used in the branch office, the analog phones can dial out using the analog trunk lines in the branch office itself (instead of going through the IP PBX at the head office – this case is not shown in the diagram). Also, the SPA 8000 analog voice gateway can itself register with an ITSP (using a SIP Trunk) to make VOIP calls from all the analog phones connected to it from the branch office itself.
In addition to the analog to IP / IP to analog conversions, even 3-way conference calls are supported by the analog voice gateways (without an IP PBX). Even the Music on Hold (MOH) feature – to play a tune when the incoming callers are kept on hold is supported. Both the devices need to be supplied with electrical power and with SPA 8800, even if the electrical power goes down, the analog phones connected to it can still access the analog trunk lines connected to it.
Click here to find out the latest price of Cisco Small Business SPA 8000 ATA (8 x FXS ports) in Amazon (for US customers) and click here to find out the latest price of Cisco Small Business SPA 8800 (4 x FXS ports & 4 x FXO ports) in Amazon (for US customers).
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