Welcome all forum members, I'm newbie at PBX and managed telephony, but I'm familiar with computer networking. I'd like to create my first PBX system working in my company. The goal I want to achieve is: Technical: - use only one number (GSM card) - ability to answer call with Android phone connected to company Wi-Fi network Customer support: - wecome message on answering call - informing customer about position in line (if more than one is calling) - informing about working hours if customer is calling off working hours Can anyone help me where do I have to start to achieve this? What hardware and software would I need? I'd rather prefer open-source, cost-effective solution. Many thanks in advance!