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Customer Service Level Agreements (SLA).

Comprehensive details on CallTower’s Customer Service Level Agreements, including scheduled maintenance windows for solution updates.

Scheduled Maintenance

At its election, CallTower may schedule maintenance during a standard maintenance window on the third Friday of every month from 10:00 PM to 4:00 AM Mountain Time and will provide Customer with a 1-week notice of all scheduled maintenance; notice of Scheduled Maintenance shall be provided to Customer’s designated point of contact by a method elected by CallTower including telephone, email, fax, or pager. CallTower may schedule a weekly certificate upload every Friday at 12:00 AM Mountain Time on the Skype for Business platform. This process has no customer impact and services remain functional during the upload. Such service unavailability shall not be considered a factor in determining Service Level Availability.

Service Level Availability Process

If Customer opens a trouble ticket with CallTower Customer Support within 3 days of Customer’s failure to access CallTower’s Service, and CallTower determines in its reasonable commercial judgement that the Service is unavailable due to an outage caused solely by the items of the Service managed by CallTower, that Service interruption will be used to calculate Service unavailability to determine the remedies provided below.

Service shall be deemed by CallTower to be unavailable if CallTower’s servers are not responding to hypertext transfer protocol (HTTP) requests, or CallTower Services are not responding to telephone calls received through the public switched telephone network (PSTN); CallTower’s records and data shall be the basis for all Service availability calculations and determinations. Unavailability of CallTower’s Service due to (a) acts or omissions by the Customer, its agents or any user of the Service authorised by Customer; (b) Customer power outage; (c) network unavailability or interruption external to the CallTower data centre or outages resulting from services from Tier 1 partners such as, but not limited to, Sprint, Level3, XO, and Windstream, even if contracted by CallTower for the benefit of Customer; (d) scheduled maintenance; (e) interruptions relating to account codes, client network connexions and environment, client Outlook, and DNS services; (f) external network connexion interruption by a third party even when contracted by CallTower on behalf of Customer; (g) connexions brought down by any company or individual (including Customer) outside of CallTower; (h) Customer’s applications, equipment, or facilities; or (i) events of Force Majeure shall not be deemed Service unavailability for the purpose of these Service Level Agreements. Where CallTower deliver its Services over the Internet (outside a private network) to offices or individual users CallTower cannot guarantee availability and are thus expressly excluded from these Service Level Agreements

Service Level Agreements

CallTower’s Service guarantee ensures that Customers receive the following levels of Service:

Service Level Commitment For Voice Services

99.95% uptime in any calendar month

Service Level Commitment For Voice Messaging Services

99.95% uptime in any calendar month

Availability Guarantee

CallTower’s Availability Guarantee declares that the specified CallTower Service (Voice and Messaging services) will be available 99.95% of the time. If CallTower fails to meet this Guarantee during any given calendar month, Customer’s account is eligible to be credited for the value of the affected service.


At Customer’s request, the prorated credit will be in the amount of one day of the Customer’s cost of the affected CallTower Service for each cumulative hour of Service unavailability that falls below the SLA of 99.95%.

Updated October 2021