Linking Of Two Ericsson MD110 Switches

I am currently working to link to two Ericsson Switches :

Site A is Ericsson MD110 BC-12 Switch and

Site B is Ericsson MD110 BC-7.2 Switch. Both has ISDN User license. Can I achieve linking the two?

More so, if I cannot, Can anyone help with How I can get an ISDN Q-SIG license to load into the switch to achieve linking?

Paul Agbor