E21 – 4F Counting CIA Numbers Station Profile

First discovered in 1981, E21 is a numbers station that’s very similar to that of E05, using almost the same format for the messages. The majority of the time the station used 4-figure groups instead of the usual 5.  In some rare instances it did use 5 digit groups.  The station ceased operations in March 1995.

It’s voice is also another version of E05’s, with a higher pitch and tempo.

4 Digit Groups Recording

5 Digit Groups Recording


E21 Station Format

Preamble Message Repeat Outro
430 430 430 1234567890 Ten 1 kHz beeps play Count 120 1098 5131 … Repeat Count 125 4052 7201 … End
3-figure ID Counting Group count 4-figure single groups Group count 4-figure single groups
Repeated for 10 minutes Repeated 2x Repeated 2x


Numbers Station Summary

Nickname: 4F Counting
Activity: Inactive
Emission Mode: USB, USB + Carrier
Voice Summary: Automated woman’s voice with an American accent.  Another version of E05’s voice with higher pitch and tempo.
Believed Country of Origin: USA
Counterpart stations: E05, V05, G05


Simon Mason’s E5 Page