EXFO FTB-500 (Window XP) - Manual (Page 71)

Setting Up Your FTB-500
FTB-500 61
Installing a Headset or Speakers
Installing a Headset or Speakers
The FTB-500 comes with an internal speaker for audible feedback, but
there are times when you might want to use more powerful speakers.
Other types of environment may warrant the use of a headset instead of
the external speaker. You can use any commercially available headset or
speakers having a 3.5 mm connector.
To connect a headset or speakers to your FTB-500:
Connect the external speakers or the desired headset in the Audio Out port
located on the right side of the unit.