<?php

namespace AbleCore\Fields\FieldValueTypes;

use AbleCore\Fields\FieldValue;

class PhoneNumberFieldValue extends FieldValue {

	/**
	 * Generates an iPhone-friendly link to the telephone number.
	 * @return string
	 */
	public function link()
	{
		return l($this->value, 'tel:' . $this->number());
	}

	/**
	 * Generates an iPhone-friendly version of the telephone number.
	 * @return mixed
	 */
	public function number()
	{
		return str_replace(' x', ',', $this->value);
	}

}

<?php

namespace AbleCore\Fields\FieldValueTypes;

use AbleCore\Fields\FieldValue;

class PhoneNumberFieldValue extends FieldValue {

	public function link()
	{
		return l($this->value, 'tel:' . $this->value);
	}

}

--- 
+++ 
@@ -6,9 +6,22 @@
 
 class PhoneNumberFieldValue extends FieldValue {
 
+	/**
+	 * Generates an iPhone-friendly link to the telephone number.
+	 * @return string
+	 */
 	public function link()
 	{
-		return l($this->value, 'tel:' . $this->value);
+		return l($this->value, 'tel:' . $this->number());
+	}
+
+	/**
+	 * Generates an iPhone-friendly version of the telephone number.
+	 * @return mixed
+	 */
+	public function number()
+	{
+		return str_replace(' x', ',', $this->value);
 	}
 
 }
Add number() and update the link() method to use it.
