Audio Delay, internal calls, GRP2634-UCM6304-GRP2634


The audio delay from microphone to ear piece (diffrent handsets) is over 400ms. But when I ping between each of the pieces there is less then 1ms. All devices are on the same Subnet and VLAN.


Thanks Malcolm



I have submitted a ticket. And will update as we progress.
Thanks Malcolm


Check packet in ucm for this call. It came late or not ?
If yes switch to phone and see if packet leave late.


Did you find a solution for this problem?


Buenos días, hay solución para esto? también tengo el mismo problema. Al levantar el auricular el llamante escucha después de 3 o 4 segundos. Ya en el transcurso de la llamada no hay problema.


depends on your setup… what sort of call? internal extension to extension or pstn/sip to extension?


telefonos grp2602, ambas llamadas, internas y externas


is your ucm firmware uodated?


la ucm esta en



muchas gracias, procederé a actualizar.


your welcome… The audio issue is not reported in the update but grandstream support will ask you to update it first and reboot.

if it continues try with a softphone like zoiper to see if it is handset hardware related.


Si, ya veo que no se menciona, pero si es de hardware del teléfono seria en todos, son nuevos, los adquirí en agosto.


Don’t forget to upgrade the firmware on the handsets - i believe there are firmware versions that are better than others.

The GRP handsets seem to have been the most worked on firmware of all of the handsets to my knowledge, perhaps because of the wide variety of features.


Good evening.
We have the same problem with GRP2604p phones. The delay at the beginning of the call a few seconds, then everything is normal and there are no problems.
There are no problems with other models, only with this one. All the updates are installed.
Packet capture on the PBX showed that at the beginning of the call there are large losses and delays.