The front of the NTU 7 has the following indicators and test facilities:
- Four separate data rate indicators (green lights). These indicate the user rate in use and also double up as a power on indicator (as one of them will always be on).
- A FAULT light (red). This indicates that the unit is in a fault state. This may be due to a self-test failure, the loss of line sync or an invalid communication message.
- A LOCAL LOOP button. Pressing this applies a customer facing loop.
- A LOOPBACK button. Pressing this applies a network facing loop.
- A REMOTE LOOP button. Pressing this applies a loopback at the distant NTU.
A yellow light, one for each loop, will come on to indicate the presence of the respective loop.