What hardware is required to add an M340/M580 expanded backplane?

Adding an expansion rack requires an Extension rack Module (BMXXBE1000), Extension rack Cable and Terminators.
The BMXXBE2005 is an Extension rack kit that contains everything that you need including:

• 2 BMXXBE1000 extension rack modules
• one BMXXBC008K 0.8 meter extension cable
• one TSXTLYEX set of 2 line terminators

Other cable lengths available:
BMXXBC015K - 1.5m extension rack cable.
BMXXBC030K - 3m extension rack cable.
BMXXBC050K - 5m extension rack cable
BMXXBC120K - 12m extension rack cable