diff --git a/pool/base.php b/pool/base.php
index e9e4a6c6..53426167 100644
--- a/pool/base.php
+++ b/pool/base.php
@@ -272,6 +272,21 @@ function safepass($pass)
  return true;
 }
 #
+# simple test without checksum validation
+function btcaddr($addr)
+{
+ $c0 = substr($addr, 0, 1);
+ if ($c0 != '1' && $c0 != '3')
+	return false;
+ $len = strlen($addr);
+ if ($len <= 26 || $len >= 37)
+	return false;
+ $rem = preg_replace('/[A-HJ-NP-Za-km-z1-9]/', '', $addr);
+ if (strlen($rem) > 0)
+	return false;
+ return true;
+}
+#
 function bademail($email, $isold = false)
 {
  if ($email == null || $email == '')
diff --git a/pool/page_pplns2.php b/pool/page_pplns2.php
index e759f2f2..e8cbc9af 100644
--- a/pool/page_pplns2.php
+++ b/pool/page_pplns2.php
@@ -51,10 +51,8 @@ function calctx($ans, $count, $miner_sat, $diffacc_total)
 	}
 	if ($payaddress == 'none')
 	{
-		$c0 = substr($username, 0, 1);
 		$parts = explode('.', $username);
-		$len = strlen($parts[0]);
-		if (($c0 == '1' || $c0 == '3') && $len > 26 && $len < 37)
+		if (btcaddr($parts[0]) === true)
 			$payaddress = $parts[0];
 		else
 		{