Centralise UCM in geographical location


That should be okay from the office to the home and vice versa …

do you have the UCMs in Route mode or Switch ?
Are you using LDAPP between the units?
Have you tried using IAX extensions between each location in case it is a router causing the issue?


My UCMs is in Switch mode.
I’ve not set up any LDAP and IAX configuration before as one of the personnel from HQ came to teach us how to use Grandstream but he only went to the seminar talk and only manage to capture some of the basic functions of Grandstream.

He only gave us information on how to set up extensions, VoIP trunks, Outbound routes, SIP settings, RTP settings, Network settings and DDNS settings.

I faced lots of problem when trying to make the system work but still have to thanks for the help from all the forums GURUs, I managed to get some of the things worked.

And I need to mention some things, our products are not using any of the Grandstream IP Phones, we are integrating something like those IP intercom door system with Grandstream UCMs. Thus, I think LDAP would not work for this case, I could try IAX configuration. Is it possible to point some direction of using IAX?



You mentioned 2 x UCM’s - between the 2 x UCM’s you can create an IAX trunk and also LDAPP which will solve extension to extension dialling and also audio I believe.

Look at the trunk area. Should be a button for create IAX trunk - you may have to use the DDNS name for the host.
LDAPP and IAX information are on the Grandstream website


Hi all,
Have to revive this post as I have one question to ask.
Managed to do this setup and is working fine.
Just to question, can 2 interconnected grandstream use 1 Analog line to do follow me?
Like i have Grandstream A and B interconnected together, and only 1 Analog line connected to Grandstream A, but if the call made on Grandstream B extension is unavailable, it will direct to Grandstream A to use the analog line to do “Follow Me”.


Does this mean that there are other lines as well? My take is yes as long as the originating call is not also using the one analog line that is used for the outbound follow-me.

However, keep in mind that the outbound follow-me being an analog line means that anytime that line is used, there is the likelihood that the CID for that line will be exposed and therefor an invitation for those seeing it to start using it to call back. While I realize that the intent is for a follow-me and that only the follow-me recipient may be the only one who will see the CID, I do not know that so, offer the warning.

You should first set the UCMs up with inbound and outbound rules so that a call from UCM (A) ext 1 can place a call to UCM (B) and that the desired trunk can be reached. Presumably, you will use a prepend to the desired number with a strip to send the call to the other UCM for hand-off to the desired trunk and that side will do the strip.


Thanks for the reply, however I don’t really get what you mean here. Do I have to make a dummy ext on UCM (B), like when I call to UCM (A) ext 123 and if ext 123 is unavailable it will direct to UCM (B) dummy ext 234, then use “Follow Me” to analog?


Read the attached it will instruct on how to peer as well as share trunks.