calls from TDM lines and SIP trunks and what caller ID is displayed. Other phones on the same carriers SIP trunking service: Ask if the caller ID is correct and be aware of the call setup time and overall call quality. IVR systems: Test the connection via the SIP Trunk to IVRs that will be used by the end users such as airlines flight status check number (1-800-UNITED1) or a movie information hotline (1-415-777-FILM). Fax calls: Both long (such as 50 pages) and short (such as 2 pages) duration fax calls should be made to ensure that the SP performs as expected. Nonvoice Band calls: If you have a plan for nonvoice band calls (that is, low speed modem, Baudot connections, and SO on) to be supported on the SIP trunk, these types of calls should be made in the trial. In summary, the goals of a pilot implementation of SIP trunks should be to understand the SP offering and to ensure that the level of expertise that the IT department has for SIP trunking and the transition from TDM to SIP trunking is adequate to ensure a suc- cessful large scale implementation of SIP trunking throughout the company. Phase V: Transitioning a Live Department to SIP Trunks The first live transition to SIP trunks from solutions that were previously live on TDM trunks can be complex and stressful for an organization. You need to select an area that is appropriate for the first live deployments. A successful first transition of SIP trunks is contingent upon many things, such as the quick and accurate porting of phone numbers and the quality of the calls over the new infrastructure and leads to further deployments. With large companies, after a pilot is completed, the order of transition of different users groups that is often undertaken is shown in Figure 3-1. Each company has different con- siderations for which area is appropriate for the first large-scale transition to SIP trunks. Some of the considerations of which area to transition first include the complexity of the transition and the cost-savings that will be seen with the transition.