4 digit phone numbers

Over the past few days I've received calls on my cell phone from 4 digit numbers, e.g., 5012. I don't answer calls unless I know who is calling, so I don't answer these either. I tried to call the number from another phone (land line), but the call won't go through. Anyone else been receiving these calls?

I'll bet those 4 digit phone calls are from an extension as I get a 4 digit number when my daughter calls me from her work phone which I know is her extension number.

More and more of that since many calls are sent through the cloud, even by the two largest phone companies, one of which I work for. I've been getting calls showing up as "+xxxxxx" where the "+" equals an international call, and the "xxxxxxx" are the digits being passed to me through the cloud. I just found out today that one doesn't need to dial "011" anymore for international calls. Many cell phones like iPhones, Androids and the sort have a "+" on the zero key, and if one holds the zero long enough, that it will toss a "+" up, and then all one has to do is dial the country code, city code, and...not dial "011" in front of an international call Heard have been doing that for some time everywhere but America. As a matter of fact, the switching equipment that I'm installing right now, "011" probably could still be programmed for insertion, but we aren't, and are programming "+" to be inserted into the front of international calls, followed by country codes, and right down the line.

Truth of the matter is that if the equipment calling you is "customer" owned, like a PBX, they can pretty much send you whatever they want to. I do it all the time, especially when calling my boss. I might be in Iowa, and his caller ID might come from Texas, or even the white house if that's where I want to call him from. He then asks me why I'm calling him from Alaska, Florida, the white house, or wherever and I'll jokingly remind him that he sent me to New Mexico, Montana, or wherever I want to call him from. I do it jokingly, but have heard that private investigators do that a lot, especially if they're after someone for money owed to someone. The Caller ID on their phone might show up as the FBI, so they answer it because they're too afraid not to. They're read the riot act from someone they think is an FBI agent, or cop about bounced checks or whatever, and demand to be met somewhere to fork over the money, or be hunted down and cuffed and hauled off. The person being called knows that they did what they're being told that they did, so they either run and hide for the rest of their lives, or show up to fork over the money or whatever, only not to be met by the FBI agent or cop that they thought was showing up. That may not be totally legal, but neither is bouncing checks or such, and it happens all of the time.

Mark