diff --git a/modem/api_validations.py b/modem/api_validations.py
index e3b50021..97bbd14d 100644
--- a/modem/api_validations.py
+++ b/modem/api_validations.py
@@ -1,7 +1,8 @@
 import re
 
 def validate_freedata_callsign(callsign):
-    regexp = "^[a-zA-Z]+\d+\w+-\d{1,2}$"
+    #regexp = "^[a-zA-Z]+\d+\w+-\d{1,2}$"
+    regexp = "^[A-Za-z0-9]{1,7}-[0-255]$"
     return re.compile(regexp).match(callsign) is not None
 
 def validate_message_attachment(attachment):