VoIP vs ISDN 30

[AtomCom2001]

Hi,

I am currently using a standard ISDN 30 based PBX (Swyx) with Voip clients, (Both desktop handsets, on Windows clients).

I was wondering if it was now time to move to something like asterisk and take advantage of full VoIP?

 

[drsox]

Depends, ISDN is probably more reliable than a dedicated internet line for VoIP.
I have played with the idea of moving an office I manage IT for.. but the "fluffy" problems that the internet randomly develops (routing issues etc.) make it a scary thought, even with the massive cost savings.

Tom - www.mouselike.org

 

[uno]

ISDN will always be better than VoIP - just due to latency differences.

However, choosing the right VoIP provider and more importantly, the right connection can pay off and give a connection that you could not tell apart from the ISDN solution.

Few things to consider though. Having a backup ADSL line in case the first one has a fault and maybe even a router that can fail over to that line should it be required. (A bonded broadband line might be a possible option for you but some of the newer solutions can have problems with the real time, latency sensitive nature of VoIP traffic).

I helped convert a friends business from 10 exchange lines to full VoIP. They (now) use a Vigor 2820 IPPBX to manage the calls internally with that connected to ADSL and the secondary WAN into a Speedtouch 546, to a backup connection.

Works very well and saves hundreds a month in costs for equipment lease, rental and calls.

They use a Gradwell package with inclusive UK calls for around £15 a month.

Matt

 

[hshamallakh]

Hi

How did you configure the gradwell trunk with the 2820 IPPBX? i would really appriciate your help, i have the same package and i couldn't find any support regarding this on both Draytek and Gradwell site. Thanks

 

[uno]

I don't remember i'm afraid. It was some time ago.

Matt

 

[hshamallakh]

Thanks Matt for your quick reply,

The problem is that Gradwell does IP authentication and i am sure my router IP is the one registered, but i simply can't get a successful connection. can't you recall any of the configuration .. i can post a screen shot of the SIP trunk configuration page.

Thanks again

 

[uno]

Sorry, I really can't recall what we did.. It was after a long 10 hour night stint to replace their whole telephony network with many caffine-based drinks.

Matt

 

[LeeH]

It depends how business critical it is for the voice lines, VOIP going over a normal DSL line will have all the same issues as the DSL line itself suffering from bandwidth limitations depending what product 448 upload etc.

ISDN30 does have a SLA on it where as the DSL doesnt so it is critical then ISDN30 would be your best bet.

Other options would be leased lines and run the VOIP over that which has a SLA and most have a DSL back up for the fail over, it does all dpend on budget and the requirements of the customer.

 

[namratasnv]

It depends how business critical it is for the voice lines, VOIP going over a normal DSL line will have all the same issues as the DSL line itself suffering from bandwidth limitations depending what product 448 upload etc.

ISDN30 does have a SLA on it where as the DSL doesnt so it is critical then ISDN30 would be your best bet.

Other options would be leased lines and run the VOIP over that which has a SLA and most have a DSL back up for the fail over, it does all dpend on budget and the requirements of the customer.

I think this can be the better option for me, like using leased lines and running VOIP over that can be better for all the requirements that are worth.

Thanks

 

[TheVoIPMan]

Hi,

we'd never recommend using more than a couple of VoIP concurrent calls over a normal business ADSL broadband line even if using G729 codec rather than G711.

It's very important to know where the path of the call flows from your VoIP providers SIP servers to your broadband connection. If the call goes over the general Internet then this is what I'd call "The Wild West" and anything can happen.

I'd recommend using a VoIP / Broadband provider that can GUARANTEE you a set number of calls and can also GUARANTEE you a service level agreement on packetloss, delay and jitter. If your VoIP / Broadband provider can do this then great you're onto a winner.

Gamma Telecom (who are a wholesale provider) can offer circuits guaranteeing 5 or 10 concurrent phone calls using G729. This is delivered using a combination of 1:1 LLU circuits or BT datastream should they not be available. We offer these as an authorised Gamma Telecom re-seller.

Send me a message if you'd like to know anymore technical information.

Thanks

David @ Talk Straight

 

[albert53]

In my opinion Isdn is not reliable than VoIP. Its also depend on the business that which types of business you have and what are the requirements of it.