How to reduce long distance call charges using IP PBX – Grandstream GXE 502x

This article details four options that you could set up with an IP PBX (Grandstream GXE 502x in particular) to reduce long distance calling charges for your company/ organization.

One of the primary influences behind the driving of IP Telephony and VOIP adoption is its ability to reduce long distance calling charges. The following four options can be implemented together or individually to achieve the same, depending upon your usage/ locations.

Option 1: Inter-branch Voice Communication over the IP Network

Reduce call charges using IP PBX for Inter branch callingIn the first option let us explore the inter-branch calling. In a typical organizational set-up, there would be a HO with the IP PBX/ IP Phones, branch offices (one shown here) with their IP PBX/ Gateways and IP Phones too, and some remote users / traveling personnel accessing the IP PBX through fixed or mobile broadband technologies over the Internet.

In any company, a lot of calls happen between the various branches of the same company. Techniques like PRI Centrex, Cellular CUG does reduce the internal call charges a bit, but a VOIP/ IP Telephony implementation across all the branches and HO would use the data network (Internet/ MPLS/ Leased Lines) to transport voice as well. So, the next time you call to any of your inter-branch number, the IP PBX would automatically route those calls to the IP WAN Network instead of routing them over the PSTN networks, which saves a lot of recurring expenditure. The architecture diagram for this scenario is given above.

Option 2: Using an Internet Telephony Service Provider to route calls to the PSTN networks over the Internet

Using an ITSP (Internet Telephony Service Provider) to reduce call chargesOne more easy way of reducing long distance communications with an IP PBX is to use the Internet to make your long distance calls to any land line and cell phone around the world. In fact, in some countries, you can use the Internet to make STD and Local calls to any land line and mobile phones as well. But this option might be more suitable for companies that make a lot of outgoing calls to many phone numbers in a particular country/ group of countries because, it lets you to negotiate a bulk calling rate for that country/ group of countries with ITSP’s. An ITSP is the Internet Telephony Service Provider and usually your corporate IP PBX is connected to their network using a SIP trunk provided by them. What they basically do is, take the call originating from your company IP PBX over the Internet to an Internet gateway in the target country (where the call is to land) and then from there, they connect the call to the local PSTN/ Cellular network. Since the call travels on the Internet for the majority of the long distance, the overall International call charges become less. Skype is a good example of an ITSP.

Option 3: Accessing a Remote PSTN Gateway from the IP PBX over the Internet

Accessing Remote Gateway from Grandstream IP PBX to reduce call charges

If you have offices in multiple countries, you could take advantage of this method offered by Grandstream GXE 502x IP PBX and Grandstream GXW FXO/ PSTN gateways. This method is very similar to the previous method, but here we are going to use our own infrastructure to take the call across the Internet/ Leased Lines and connect to the Local PSTN Networks using FXO/PSTN Gateways.

A FXO Gateway is a device that connects to an IP Network on one end and connects to FXO (Analog Trunk Lines) on the other end. This gateway has its own IP address and needs to be registered with the IP PBX, in order to bridge the calls coming from the IP network on to the PSTN network.

So, here, when a call originates from any one of the IP Phones connected to the IP PBX (Local location, head office), based on the country code, Grandstream GXE 502x IP PBX can automatically route the call through the Internet / Leased Lines to land on the Grandstream GXW FXO/PSTN gateway that is placed on the remote International Location. From there, the call is passed on to the PSTN (Analog Trunk Lines) to reach a local number in the international location. In this case, there are not much charges for the call traveling over the Internet/ Leased Lines and only the local calling charges (over the PSTN network) gets charged. So, this is like sitting in your office in USA and making a call to any mobile or land line number in UK and still get charged only according to the local calling rates in UK!

This Option is not allowed in certain countries (like India, for example), so please check with your local regulations before applying it to your scenario in your country.

Option 4: DISA: Direct Inward Station/ Subscriber Access – Since this topic has already been covered in a previous article, please click on the link to read it.


And yes, also do read a related article – Ten best reasons for SMB companies to switch to VOIP using Grandstream GXE 502x IP PBX which basically highlights all the other reasons (apart from reducing long distance call charges) about why an organization needs to implement VOIP / IP Telephony across all its branches – particularly the small and medium businesses which have many branches across various locations.

If you live in the United States and you want to implement IP Telephony, you could buy the Grandstream IP PBX from Amazon.

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