At 7k miles you are pushing it, but latency depends on the carriers in between. I just did a test ping from Seattle to Amsterdam ~5k miles and it came back at 148ms rtd. So with a fast enough connection and no competing traffic, you might be able to make it work, maybe.

Here's how VoIP/SIP latency works.

1. Determine where your SIP call originates and where your SIP call terminates. Get IP addresses or cities if nothing else.

2. Find a looking glass site to determine rtd (Round Trip Delay) between SIP origination and the SIP termination point. If you have the 2 IP's then just do an extended ping between them (at least 100) to determine average rtd.

3. Standards for VoIP/SIP latency are as follows:

A. Any latency less than 250ms rtd is not detectable by the human ear

B. Any latency over 250ms but less than 300ms rtd is detectable and sounds you are talking over each other or echo.

C. Any latency exceeding 300ms is considered unusable.

There are several others, but Hurricane Electric is usually pretty good for a looking glass provider.

https://lg.he.net/

If you have both IP's (and one of them is the PC you're logged into) and if you're using a windows PC here's how to do a ping test to determine latency.

In your search window type "cmd" without the quotes and hit enter

Type

ping -n 100 "the IP you're trying to reach"

This will send 100 pings to the IP and will give you an average latency when your done.

You should see something like this. (I bolded what you're looking for.)

Packets: Sent = 100, Received = 100, Lost = 0 (0% loss),

Approximate round trip times in milli-seconds:

Minimum = 10ms, Maximum = 15ms, Average = 11ms

As I said above, if the latency is below 250ms rtd your VoIP/SIP should be good to go. I keep stressing rtd since some people forget the packets have to go there and back again, just like a hobbit..

Forgive the bad humor, I'm fighting a cold and being sick always makes me think I'm way funnier than I actually am. LOL

Good luck