The O/S needs to see the devices before you can config them in NBU. Can you see the robot and tape drives in Window Device Manager?
Which Windows version? 32- or 64 bit?
Also have a look at the Device Config Guide on your Docs cd/dvd or exftpp.symantec.com/pub/support/products/NetBackup_Enterprise_Server/290200.pdf

Remember to stop and disable Removable Storage Manager service.

Once  you are done with Zoning.

1 Check for Drives/Medium Changers drivers from your Hardware vendors and install them as per their guidance.

2 Once you done with Driver installation, you will be able to see all drives and medium changers in Compmgmt.msc- > Device management.

3 Now you are ready to configure NetBackup things. Click on your Master Server name that is in top of Activity monitor option.

4 From the right panel->Configure Storage Devices

5 Go with the Wizard, that will show the details of drives/robot connected to your server. verify all things and finish up the wizard.

6 So now your drives and robots are controlled by netbackup.

7 Just go ahead and do a test backup and restore.

Cool...

Mark my Comment as solution, if you are satisfied on my post.

are properly zoned to the master server.  Like Marianne mentioned if you can not see the tape drives in device manager, it may be a zoning issue.

What do these commands report on your master server:
$ scan -changer
$ scan -tape

Thanks all for help !

I'm connected complete to Tape Library . The problem is OS dont' have driver for Tape .

My system use Tape Library SL48  .

-- I read Netbackup Device config guide book but I don't understand different of robotic Type and communication method  robotic control software use  API and SCSI .

My Tape is TLD robotic type . How Do I check communication method is API or SCSI ? 
Please help me!

What kind of tape drive is in the SL48?
If you are using 32-bit O/S, you can use the Veritas tape driver (on your install media or seer.entsupport.symantec.com/docs/287850.htm).
If your O/S is 64-bit you will have to download the driver for the make/model tape drive in the library.
Ask your SUN/STK supplier to explain different communication methods.
SAN connectivity emulates SCSI, so my guess is it will be SCSI. API should be something like ACSLS Software, where the robot is connected to a separate server with its own software (ACSLS) to control the robot.

Thanks you so much .

I understand it

Have a nice week.