Perle Systems 833IS - Manual (Page 36)

Telephony Cabling
20 Perle 833IS User Guide
To enable termination, use the supplied jumpers (attached to the jumper block) to
jumper the two top jumpers together and the two lower jumpers together.
To disable termination, remove the jumpers.
Note that a BRI U interface has no user adjustable termination.
! Enable 100 termination - Jumper block
! Disable 100 termination - Jumper block