[Serusers] Link NEAX2000 and Ser sip server

Dear All, I am very new to SIP matters. Currenly I am configuring sip server (SER) for our Faculty and in the near future I am looking for connecting our Digital PBX with sip server to communicate with each other via some layer three equipment such as LAyer 3 swich (3COM 35000) which is core switch for our faculty network. But I have liittle idea on technical maatters regarding this. Some people say IPPAD will do the job, others say ISDN card will do the job. Can anybody suggest me anythig regarding this matter. IF spmebody has done this one earlier, I would very much appriciate if I can share that experince. Rgrads Aruna ---------------------------------------------------------- S. A. S. Lorensuhewa Head, Department of Computer Science University of Ruhuna, Matara, Sri Lanka Telephone: 0094 (0)41 2227019 Fax: 0094 (0)41 2222683 Email: lorensuhewa(a)cc.ruh.ac.lk, aruna(a)cc.ruh.ac.lk