Local commercial phone service must be provided in support of Continuity Of Operations (COOP) and Fire and Emergency Services (FES) communications.

Voice phone services are critical to the effective operation of the DoD mission. We rely on these services being available when they are needed. Additionally, it is critical that phone service is available in the event of an emergency situation such as a security breach or life safety event. The ability of maintaining the ability to place calls to emergency services must be maintained. While the DoD voice networks are designed to be extremely reliable, such that COOP is supported, there is the potential that a site will be cut off from the DoD network. Based on this fact, each physical site must maintain local commercial phone service in the event the site is cut off. While this works to maintain local emergency service availability for security and life safety emergencies, it also provides the capability to make calls between DoD sites using the commercial network. An additional, non-IA benefit is that this supports the ability to make local calls without having to pay toll charges to call a local number via some distant regional access point. Local phone service can be delivered in a number of ways, all of which meet this requirement, while some of them must meet additional requirements to secure them.

Delivery options are as follows:
- PRI or CAS TDM trunks
- Analog phone lines

The following are some examples:
- A large site may use PRI, CAS, or POTS analog trunks connected to the site’s PBX.
- A small site or office attached to a large site.
+ May have a PBX and be served similar to a large site.
+ May be served by several analog phone lines terminated on Voice Video Endpoints.