In U1900 series unified gateway, which of the following statements are CORRECT about the relationships among prefixes, office routes, office route selection codes, and trunks for eSpace U1900?…

Question

Options

• AA prefix can map only one office route selection code.
• BAn office route selection code can map only one prefix.
• COffice route selection codes and office routes have a one-to-many relationship.
• DAn office route can map the trunks of different types.

• A
  77% (27)
• B
  9% (3)
• C
  14% (5)

Explanation

A is correct because each dialing prefix uniquely resolves to exactly one office route selection code - the system needs a deterministic, unambiguous path for each dialed pattern. D is correct because an office route acts as a trunk group container and can bundle trunks of different types (e.g., ISDN, SIP, analog) together, giving the gateway routing flexibility and redundancy.

B is wrong because the mapping is asymmetric in the other direction - multiple prefixes can share the same office route selection code (many-to-one), so a single selection code is not limited to one prefix. C is wrong because the one-to-many relationship actually exists between office routes and trunks, not between selection codes and office routes; one office route selection code maps to one office route, not many.

Memory tip: Picture a funnel - many prefixes narrow down to one selection code → one route → but then fan back out to many trunks of various types. The "one-to-many" lives at the route-to-trunk level, not at the selection code-to-route level.

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