Problems when using AltSoftSerial library on Arduino Uno R3


I have a project needs more serial ports to achieve input and output signals,
but, I use the board of Arduino Uno R3, not Arduino Mega 2560.
Arduino Uno just only have one serial communication,
so I try used AltSoftSerial Library (AltSoftSerial Library, for an extra serial port) to build more visual serial ports.
Unfortunately, there are some problems occur.

It is just a sample code I depict the situation without connecting any external device...

#include <AltSoftSerial.h>

AltSoftSerial altSerial(8, 9);

void setup()
  Serial.println("Hello Serial");
  altSerial.println("Hello AltSerial");

void loop()
  char c_serial, c_altserial;
  // Write it.
  c_serial =;
  Serial.print("Write it to Serial: ");
  altSerial.print("Write it to AltSerial: ");
  // Read it.
  c_altserial =;
  Serial.print("Read it from AltSerial: ");

In the serial monitor, the result is ...

Hello Serial
Write it to Serial: ÿ
Read it from AltSerial: ÿ

The message can be printed from serial port,
but there is nothing from AltSoftSerial (can not print out the value I need).
My environment of development is Arduino IDE 1.0.5, and I use Arduino Uno R3.
Is there any suggestion? Thanks a lot!!