Interphase Tech iSPAN 5535 PRI - Manual (Page 124)

Setting Port and Clock Modes
104 Interphase Corporation
Loopback Mode
Loopback mode is a transmission state in which the signal
received by the port is returned to the sender. Use this mode
when the remote end (the Telco, for example) is testing your
line; all information sent is returned to the remote end.
To select this mode, select Loopback mode on the Port Test
Configuration dialog (shown in Figure E-2 on page 103).
Two loopback settings are available:
• Line loopback
The signal returned to the loopback command source
consists of the full signal. Bit sequence integrity is
maintained. No change in framing occurs, and no
bipolar violations are removed. This is the default
loopback setting.
• Payload loopback
The signal returned to the loopback command source
consists of the payload of the received signal and
newly-generated ESF framing.
To select one of these loopback modes:
1. Click Options on the LineTest Configuration Dialog.
The LineTest Options dialog appears: