June 28, 2018 — This post has been updated with a few other caller ID numbers.

For a while now I’ve noticed calls coming in through my voice trunks with a strange caller ID.

That caller ID is +266696687.

At first I thought they might have been calls from an Australian 02 number with an incorrect conversion to E164 (eg: that number might have really been 02 6669 6687).

After doing some further digging I then noticed that the digits stand for ANONYMOUS as typed on a telephone keyboard.

2 6 6 6 9 6 6 8 7 A N O N Y M O U S

I have come across a few sites indicating that these calls should be blocked however in my case they are legitimate calls from people with their caller ID withheld. As such if you’re considering the same then I’d suggest proceeding with caution.

There are a few other numbers that you may see:

737 874 2883

This number translates to RESTRICTED.

7 3 7 8 7 4 2 8 8 3 R E S T R I C T E D

256 2533

This number translates to BLOCKED.

2 5 6 2 5 3 3 B L O C K E D

865 6696

This number translates to UNKNOWN.

8 6 5 6 6 9 6 U N K N O W N

86282452253

This number translates to UNAVAILABLE.