[abrown142]

Hi.

I have a strange application where I would like to get a PSTN gateway to send a "flash" to the incoming line. I think its easier if I explain how I want the sequence to work.

1) Incomming call rings PSTN line
2) Grandstream 4108 sends invite to 3cx and phone(s) ring.
3) IP phone answers and the call is connected

-- so far this is all good --

4) "flash" button is pressed on IP phone and event 16 is sent in the RTP to the 4108
5) 4108 applies a flash to the line

-- This is the bit i'm stuck on --

As far as i'm aware the 4108 will support sending a flash on the line but the invite message that is send out only supports events 0-11. I think this gets passed on the the SIP phones who don't give the option to send a flash because the event is not supported in the invite.

has anyone done this successfully before?

does anyone have any idea on the settings I need?

note: it does not have to be a Grandstream FXO device. It can be another device if people have had any joy.

[leejor]

While it may be possible, I'm thinking that the fact the call is passing through 3CX, may cause it to not work. A flash is generally not sent out on trunks going into a PBX. The flash is almost always used with residential line feature like call transfer or 3-way calling. These would not normally be on business lines/trunks fed into a PBX as the PBX itself would be performing these functions. I can't think of one analogue PBX that will pass a flash from an extension out to a trunk.

[abrown142]

Its a shame.

We are in a very tricky scenario where we are connecting to some lines where sending a flash is needed. It is another PBX we have no control over. there are a lot of politics going on and I realise there are better ways to do things but we are getting squeezed into a corner.

At the moment the RTP stream is not going via the PBX. maybe that will make a difference??

[willow]

It seems like more and more PBX manufactures are ignoring these types of features. I work on numerous systems and it seems that after a time they just stop supporting the flash features because they think that everyone has a PRI or some varient of incoming lines. when in fact alot of people still have analog lines with call waiting. I know that the Avaya IP Office supports the flash feature as I've recently installed one that needed the feature.

[abrown142]

I think we are going to deal with a smaller ammount of pain than having two phones for a period while we play with the API's in 3cx and see if we can get a dtmf sequence to fire a flash to the grandstream. the Grandstream appears to support the feature. I will find out soon, I'm going to have to do this on another project, this time not using 3cx. still want 3cx to support it for our main business calls.

[sunnylink1]

While it may be possible, I'm thinking that the fact the call is passing through 3CX, may cause it to not work. A flash is generally not sent out on trunks going into a PBX. The flash is almost always used with residential line feature like call transfer or 3-way calling. These would not normally be on business lines/trunks fed into a PBX as the PBX itself would be performing these functions. I can't think of one analogue PBX that will pass a flash from an extension out to a trunk.

Panasonic KX-TA624, KX-TA824, KX-TAW848 are just a few Analog PBX systems that pass a flash from an extension out to a trunk.

[leejor]

To be fair, the Panasonic systems you list are more of a glorified key system, with "PBX like"features. They seem to support (only?) analogue lines, which are the only type that would require (can support) a flash.

The majority, if not all new PBX's have moved on to PRI or VoIP as the primary form of trunking, but will still support analogue lines, in many cases now, for backup.
While there may be equipment (Panasonic) that supports a flash on an analogue line, it is not a "standard" feature on a business line (trunk) (other than perhaps single, non-hunting) and will be difficult (perhaps not impossible)to implement using a VoIP gateway.

If you find a way to get it to work (with a particular gateway), there are a few other forum members that have shown interest.