SIP Trunks for Institutions
SIP trunks provide scalable outside lines for campus PBXs. Here is how to size them.
An IP phone system needs a connection to the outside world for calls to and from parents, vendors and other institutions. SIP trunks provide that connection over a data link, replacing traditional PRI or analog lines.
What a SIP trunk is
A SIP trunk is a virtual connection between your PBX and the voice provider's network. Capacity is measured in channels — the number of simultaneous outside calls.
Sizing channels
Count calls at your busiest moment, not total staff. A campus with 200 extensions might only need 15–30 channels because most calls are internal. Admissions season and results days usually set the peak.
Scale with the calendar
Channels can often be increased temporarily during admissions or results periods and reduced afterwards, which is impossible with physical lines.
Number plans
Institutions can have a main number, departmental direct numbers and toll-free numbers for admissions, all delivered over SIP.
Connectivity and quality
Run SIP trunks over a reliable connection with voice prioritised, ideally a managed link from the voice provider. Consider a backup path for critical lines.
Security
Protect the PBX from toll fraud with strong passwords, firewall rules restricting SIP access and limits on international dialling.
Porting existing numbers
Keep your well-known institutional numbers by porting them to the SIP service.
The bottom line
SIP trunks give institutions flexible, scalable outside lines. UbiFi Campus Telephony sizes trunks for your calling patterns and seasonal peaks.
Learn more about Campus Telephony from UbiFi, or talk to our team.
IP telephony for campuses — department extensions, hostel intercoms, IVR for admissions and SIP trunks over fiber.
