code: public static Call create(final String to, final String from, final String callbackUrl, final String tag)  throws Exception
      {
      	assert(to != null && from != null);
      	    	
      	final Map<String, Object> params = new HashMap<String, Object>();
      	params.put("to", to);
      	params.put("from", from);
      	params.put("callbackUrl", callbackUrl);
      	params.put("tag", tag);
      	    	
      	final Call call = create(params);
      	    	
      	return call;
      }
docs: Convenience method to dials a call from a phone number to a phone number
  @param to the to number
  @param from the from number
  @param callbackUrl the callback URL
  @param tag the call tag
  @return the call
  @throws IOException unexpected error.