osmo_sccp_tcap: SSN must be an integer
diff --git a/src/osmo_sccp_tcap.erl b/src/osmo_sccp_tcap.erl
index e0e2a7d..37fbb63 100644
--- a/src/osmo_sccp_tcap.erl
+++ b/src/osmo_sccp_tcap.erl
@@ -25,7 +25,9 @@
 	Ourname = list_to_atom("sccp_ssn" ++ integer_to_list(SSN)),
 	gen_server:start_link({local, Ourname}, ?MODULE, [SSN],[]).
 
-init([SSN]) ->
+init([SSN]) when is_integer(SSN) ->
+	init(SSN);
+init(SSN) when is_integer(SSN) ->
 	ok = sccp_user:bind_ssn(SSN, undefined),
 	State = 1,
 	{ok, State}.