Programming instructions

289
Hardware Reference
Digital Service Unit
The Digital Service Unit (DSU) provides digital trunk interfaces for public
or private network access, and specialized digital functions (such as
messaging and ISDN service).
The following cards can be installed in a DSU (some cards are only
available in specific countries):
• DS1 formatter
• CEPT formatter
• T1/E1 digital trunk formatter
• BRI card (6 circuits)
• BRI card (15 circuits)
• Euro PRI card
• NA PRI card
• R2 card.
Figure 67: DSU Components