Misfunction on Snom D785 in CTI Mode

[Neonjoe]

So we just started using some Snom D785 phones in the office after the templates for them just got added. We're experiencing some issues using Windows Client CTI mode. Any time we try to place a call from CTI client, it is placing 2 calls at the same time. On the phone at extension 106, no matter what number we dial from the CTI client, internal/external, BLF or keypad, it is dialing extension 117 first. If you quickly hang up the call, it will then dial the number you actually wanted to dial. If you do not hang up, it will attempt to dial the number while it is already dialing the 117 extension, usually resulting in an error.

We are experiencing the same thing with extension 102, except that extension dials 113 before any call that you try to place from the CTI client. Again if you hang up quickly on the call to 113, your actual call will then go out right after that.

From both of these phones, if you use the BLF buttons on the actual D785 handset or dial from the keypad on the handset, the calls go just fine. If the Windows client is in Softphone mode, the call places as normal. It's only when using the Windows Client CTI where the issue happens.

 

[Saqqara]

What version of 3CX ?

How are the phones provisioned - manually , local, stun or sbc

Are the phones running the correct firmware - https://www.3cx.com/sip-phones/snom-710-720-760/

 

[Neonjoe]

15.5 SP 4

All local provision using FQDN

All on proper firmware.

The response I got from 3CX support is that BLF 1 and 2 are required to be Line Key BLFs for CTI mode to work. When I changed BLF 1 and 2 to Line Keys, CTI mode functioned properly.

I have a hard time accepting this answer as the only phones experiencing this issue are D785s. I specifically tested with D765, D745, D725, D715 and none of these require Line Keys set for CTI mode to work. Same goes with the Yealink T48s and T46s I tried it with. The D785 is the only phone failing on me of those models.

 

[StefanW]

I think I know what your issue is, can it be this:

https://www.3cx.com/sip-phones/busy-lamp-field-dss-keys/

Line Keys
The Line key button is self-explanatory and allows to create a new call/line from the phone. It also blinks on inbound calls. There used to be two line key buttons enforced by the provisioning template for all supported phones. Now it is no longer mandatory, you can have none or as many as you wish. Note that when the 3CX Client is used in CTI mode (legacy CTI), BLFs set as Line keys are mandatory on position 1 and 2! If you are using the Web client they may be placed anywhere or omitted. Snom Note: It is advised to have at least 2 BLF keys set as Line keys to make attendant transfers easy for the device user.

Additional Issue
Issue on the 785 is you have a paged blf pad, if you go to page 2 you also needed to have 1 and 2 again as line key.


Solution
Replace the 3CX Windows Client for CTI with the more advanced WebClient! the WebClient is the way forward and uses a much more advanced CTI to the IPphones!