Hello,

At work we've currently got an aira 130 with primary rate and these days 10 channels and 20 or so local extensions. We are a standard office setup, we use the basic functions, hold, transfer calls between local extensions, we also redirect incoming calls to external numbers via our PABX, voicemail -- but that's about as complicated as it gets at the moment.

Telstraclear are offering us better pricing for the channels themselves and national call rates if we can move from primary rate to "SIP trunks". I'm a bit confused as to what our options are and hoping to benefit from people with practical experience.

1. Given SIP is just a layer 7 protocol like DNS or HTTP, if we are having to pay per "SIP channel", I assume we are just paying for a certain amount of guaranteed bandwidth on TCL's separate/dedicated IP network?

2. Is retaining the aria 130 and having it somehow accept SIP trunks instead of primary rate an option? (maybe using some intermediate device?)

The savings will be in the order of $3k a year, so new hardware is a possibility. Our existing phones already operate over a dedicated network (cat5e cabling to rj45 face plates), so potentially if we had a PoE switch, the IP devices (phones/headsets) and a PABX we could be ready to go fairly easily (configuration being the hardest part)

I like all the cool potential if having a IP based PABX onsite (e.g. using a mobile phone on wifi and routing calls over the IP PABX (e.g. using 3CX) to get better call costs), but at the end of the day working phones under all circumstances is most critical.

3. We have good quality server hardware (HP Dl380 G7's) running Hyper-V for our servers, are software based solutions ready for prime time?

And if we do use a software solution combined with TCL SIP trunks, given its IP based I assume the SIP trunks just get delivered over standard ethernet with rj45 connections that can be plugged into any server?

4. Are there any dedicated hardware PABX solutions that stand out for small to medium businesses?

Thanks