Our company has 10 years old Lucent Merlin PBX with 8 analog lines and has a capability to connect T1 line but we are using just the analog lines. Then we have created about 40 extensions and using MLX digital phones. We are using Covad wireless Super T1 line for data connectivity. Now, our company want to migrate the phone system with the latest Cisco VOIP. Can you please suggest what all hardware, software and any leased lines etc. we need to implement this for about 50 users.

We also want to keep an option open in case company open any branch office in future. It may be a simple solution for you but I don't have experience in this. So, please reply me. I will highly appreciate it.