Howto:Hi folks, could you release a description how to make a "spontane Amtsholung" for a PBX User (e.g. a fax which can not be persuaded to dial a leading 0) cheers ! Lorenz

there are two ways to do "spontaneous trunk access" (is that English?), that is, to access a trunk line without a leading prefix, such as the 0.

option 1

is to have all extensions start with a special prefix, such as * or #, which does not exist for official e164 numbers.

So your extensions would have e164 "#10", "#11", ... etc. This way, they do not conflict with external numbers.

Obviously, you cannot use a trunk object then to interface to the gateway layer for outgoing calls (since the trunk object would not have a number and can thus not be called with a number).

Instead, you need to route all calls from the EXTERN interface to the ISDN.

Note that you can still have a trunk object (without an e164) to route incoming calls into the PBX so you can use the trunk objects inbound-call features (such as call forward on incomplete or invalid number etc.).

In this configuration, all users will access the ISDN trunk without a prefix.

option 2

is to configure a trunk with e164 "0" as usual.

Normal extensions would then access the trunk using this prefix.

However, selected extensions (such as a fax machine which is not expected to dial a trunk prefix), would then be registered directly to the gateway layer instead of to the PBX.

Calls from such registrations can then be routed directly to the ISDN.

This configuration may make sense anyway, since you usually don't want to apply the special inbound-call features of the trunk object to fax extensions.

If you have configured a "call forward if extension is busy" to your operator for example, then you certainly don't want that to be applied to an incoming fax call if the fax machine is currently busy.