DECT - Call Transfer Enhancement - Please?


I have (1) DP750 base station and (3) DP720 handsets. I pay for and use just one SIP account/phone number for the DP750. I want to be able to transfer a call in progress that’s being handled on one of the handsets over to another of the handsets. The only way this would be possible, presently, would be if I were to buy two additional SIP accounts and dedicate all three to the handsets individually.

That’s a problem because that triples my cost for SIP service. Why can’t the DP750 and DP720 software include a feature that lets you transfer a call in progress on one of the served cordless handsets over to another of the cordless handsets being operated by the same DP750? Of course, you wouldn’t be able to specify the other handset to send the call over to via a SIP phone number, because all three are being served with the same one. But, you could simply identify the other handset some other way. Say, by a single, unique digit assigned to each of the three, just for that purpose. And you use some menu/command button sequence on the handset to initiate the transfer, in the same type of manner you’d otherwise transfer a call to another SIP account/phone elsewhere on the network. Call it an ‘internal’ transfer for the DP750, if you like.

Does that make sense? I can’t imagine many customers haven’t proposed this already, many times. WHat do you say, Grandstream? :slight_smile:


If they’re all on the same SIP extension, simply transfer the call to your extension number and the other handsets will ring.


Yes, one of the things that we alpha tested during the beta test of these units was direct handset-to-handset communications and transfers. It didn’t go so well, and was dropped. You’re left with two options:

  1. Transfer to your own extension and let the other phone pick it up as @fmarcoux96 said
  2. Create a parking lot (if you can do it with your service) and park the call. Then pick it up from the other handset.

Having even a small PBX running on a Raspberry Pi here would be a great improvement. Your PBX would be your SIP extension from the provider and you could register as many actual extensions as you want to it from endpoints like your DECT phones. Then you’d just transfer from one extension to another.


Maybe thats a project for Grandstream to provide a small PI version for Home installs in this case or cases like this.


Our company would be happy to throw together a FusionPBX or FreePBX Asterisk-based rPi solution for just a few bucks more than the cost of the rPi. :slight_smile:


@johnpjackson, with the ITSP we use it is possible to setup four trunks on one account and then use their system (in theory as I haven’t tested it) to make calls to each other as they give can assign an extension number on their system to each trunk. No cost AFAIK as these calls are treated as internal. You also get other PBX type features as well.

You may want to look at your ITSP and see if they provide a similar service; this assumes you are connected with a VoIP service in the first place.


That’s very interesting! I just was taking a look at that way of doing it, based on your comment. I was starting to think it might really be a great way to go, but then I see that very recently, Sangoma somehow bought or took over some of those solutions and has caused their future to look less reliable:

I’ll dig around on Fusion, too though. For now I might just stay with RingCentral for a little while longer, and take the time to get up to speed on just doing my own PBX in house with a Pi. I think we’re a great size business for that. Around 10 employees.


I’m going to try that!!! :slight_smile: :slight_smile:


Why don’t you look at voip,ms -

They are very price competitive and I think will provide you with what you’d need.


Ward Mundy, the person behind nerdvittles, has some very well known opinions about Sangoma, which owns FreePBX. However, FreePBX is still a VERY popular option (and in fact, powers most of our hosted VoIP back end). I wouldn’t discount its future yet, any more than I’d discount RedHat for being purchased by IBM or Github for being purchased by Microsoft.

Also, under the hood, Voip.MS is a reseller mainly of Vitelity service, but they do provide a lot of great PBX-like services as part of their product. So @drostoker has a great idea there.

On the other hand, if you’re a 10 employee company and expect some growth, a UCM6202 would also be a great product for you (and almost all of us would scramble to sell you one!) :slight_smile:


Ok, it IS actually great to hear that this was considered and attempted. From a customer perspective it makes an enormous amount of sense. Is there any chance you might revisit the idea? All by itself, successful implementation of this functionality could effectively, possibly make a single DP750 suitable as an entire pseudo PBX for a small business. A business that needs only one phone number for outside callers to reach it, and to be able to leave voicemails at.

Using a single SIP trunk, all handsets could make outgoing calls concurrently, and all handsets could accept incoming calls to the one and only phone number of the business. And calls could be transferred from one handset to another.

Any idea what made implementation of the feature difficult? Are there limitations in the chipsets used for the hardware that just leave something simple but essential out of the mix that turn this simple idea into a minefield of ham handed work arounds to try and make up for?

Thank you for at least addressing the question so openly. You’re the first person who’s done that for me on this question, ever. I really appreciate it.


Clarification - we’re not Grandstream, just a tester of Grandstream products. At the time (two years ago, maybe? I can’t remember) the problems were related to problems between the DECT side of things and the SIP side of things not cooperating on the handsets. It was dropped because the target market is UCM users, which GS wants to sell you one of, so they would rather you buy a UCM to solve your problem than implement UCM-like features in a DP phone.

That’s my opinion, not a fact. :slight_smile:


Can’t blame them :stuck_out_tongue:


The DECT phones are not meant to be an IP PBX; that is what the UCM is for/

As I said, some ITSPs can act as your IP PBX to solve these issues (voip,ms doesn’t charge for the vast majority their feature set for example).

However, feel free to let Grandstream know - open a ticket at