186 APPENDIX B: C IRCUIT PROVISIONINGT1 Prerequisites All contact information must be available at time of installation, includingtelephone numbers and appropriate account representative contactinformation from the client’s carrier.T1RecommendationsIf the client is using standard (DS1) T1 lines, 3Com recommends that thecircuits from the T1 provider meet the following criteria:■ Framing Type — Use either ESF with B8ZS.■ Zero Code Suppression — Use D4 with AMI.■ Signaling — E&M/Wink is required.■ Start Type — Wink Start is required.Some Central Offices that use a DMS 100 switch may configure T1circuits with an option to provide outbound dial tone. This configurationdoes not provide a wink for outbound calls. The NBX system does notneed dial tone as it provides its own. Verify that the outbound channelsare configured for Wink Start.■ Line Hunting — Obtain from the telephone company the methodthey use to hunt for an available channel on the T1 span. The NBXsystem typically searches downward from high-numbered channelswhen trying to place an outgoing call. If the telephone companysearches upward from low-numbered channels for calls to the NBXsystem, conflicts are avoided.■ Circuit Type — 4-wire is required.■ DID Applications — When using DID or DNIS, 3Com recommendsordering telephone numbers that easily fit into the NBX systemnumbering plan. Although the numbering plan is extremely flexible, itis far easier to use if you have 3 or 4 digit DID\DNIS codes. This allowsfor a simple dial plan implementation.For 3-digit internal extensions, try to use the 100-499 range. Have thecarrier provide the corresponding three digits for the DID\DNISnumbers/code. For 4-digit extensions, ask for the 1000-4999 rangeand request that the carrier use corresponding four digits for theDID/DNIS numbers/code.For Caller-ID type services, the carrier must support in-band ANI.For more information, see “Ordering DID (Direct Inward Dialing)Services for T1” on page 146.
