# Fitting the header block

You can fit the header block to the base section in two ways:

- With the arrow pointing to 802.5j.
  - When you run the Diagnostics program, the Smart 16/4 Fiber AT Ringnode tests the lobe cable, and the transmit and receive circuitry (both on the Ringnode and the hub).
  - If your Ringnode fails this self-test, it is possible that your hub does not comply with the 802.5j draft-standard. Position the arrow to point to Local wrap instead.
  - If your Ringnode passes the test, it does not necessarily mean that your hub is 802.5j-compliant. If your Ringnode is the only one on your network, it may still pass the test with a concentrator that is not 802.5j-compliant. This test does not uniquely identify concentrator-type.

- With the arrow pointing to Local wrap.
  - When you run the Diagnostics program, the Smart 16/4 Fiber AT Ringnode tests its own transmit and receive circuitry but not the lobe cable. Local wrap is for hubs that use a proprietary scheme for requesting insertion to the concentrator.
  - If the test fails, contact your supplier.