DECT intercom calls

[softnetvoip]

We have multiple W53H DECT phone handsets. We ran out of the W60B base stations and are now connecting the old W53H handsets to the new W70B base stations. Calls as such do work. The only problem I noticed is that the intercom calls betweeen the W53H handsets do not work.

I now made a test where I have the following devices connected to the W70B:

1. W73H
2. W53H
3. W53H
4. W79H

Scenario1
I can make an intercom call from 1. to 4. and from 4. to 1. . This makes sense since both theese devices are of the new series.

Scenario2
I can not make intercom call from 2. to 3. and from 3. to 2. . I get "Busy here".

Scenario3
I can not make an intercom call from 2. to 1. . I get "Busy here".

Scenario4
I can not make an intercom call from 1. to 2. . I get the call to ring on 2. but I can not get to pick up the call on 2. .

Can this be solved?