[quote=“sanju”]We are going to replace an existing pbx having 80 analog phone extensions with asterisk. The requirement is i need some kind of adapter which have 1 ethernet port, 1 FXO port and 80 or more FXS port, so that asterisk server can be connected to 80 phones.
Is there any hardware like that?[/quote]
Why do you need an FXO with 80+ FXS ports, let alone an Asterisk PBX system, if you just want to replace the existing PSTN line with a VoIP line? As far as your existing PBX system is concerned, a VoIP line is merely the same as a PSTN line. So, if you still want to make use of your existing analong PBX system, all you need is an ATA device to connect its FXS port to one of the FXO ports of your PBX system. In this case, no Asterisk PBX system is needed just to replace a PSTN with a VoIP line.
As with the ATA device, you should do a Google search to find out which ATA device is more reliable. For me, I have been using several Linksys PAP2 units since 2006 and I have yet to find anyone of them giving me any problem.