I had an issue today where a client was getting a busy signal when dialing in or out. They have a Cisco phone system and their provider is Cox who uses an edgewater devices to convert the internet traffic to SIP traffic.
I accessed the BE6000 router/gateway and pinged the HP switch that has the phone system connected. I had one timeout and then it's like the connection between the router and the switch woke up. Is it possible that the connection on the uplink from the switch to the router wasn't communicating until I sent that ping request? As soon as I did that and it started communicating I was able to call in and they could call out.
Just seeing if that was a coincidence or had any significant impact.
Based on the information provided, there is no way to determine the cause why the Phone system was down. However, I can confirm that the switch would not be sleeping and come up after you ping it. It is not how switches work. The reason why your first ping timedout and received response on second one is most likely due to arp request and response, which is normal between hosts that haven't communicated directly with each other for sometime (arp timeout).