CSU Prefixes
CSU telephone numbers are assigned within the following range of telephone prefixes:
| Area Code | Prefix | Extension |
|---|---|---|
| 970 | 297 | 0300-0399, 1200-1299, 3600-3799, 4000-4599 |
| 970 | 491 | 0000-8999 |
| 970 | 492 | 4000-4999, 8000-8999, 9000-9999 |
| 970 | 495 | 2000-2999, 3500-4499, 5000-6199 |
Dialing Instructions
This section applies to making calls using VoIP phones, for information on using Teams Voice, see our Quick Reference Guide for calling with Teams Voice.
Dial only the last five digits (7+xxxx, 1+xxxx, 2+xxxx, 5+xxxx) when calling from campus. All numbers are in the 970 area code.
CSU Phone Numbers
Dial the last five digits of the University number (1+xxxx, 7+xxxx, 2+xxxx, 5+xxxx)
Non-CSU Phone Numbers & Long Distance
Dial 8 + 1 + Area Code + 7-digit number for all off-campus calls (8+1+xxx-xxx-xxxx)
International Calls
Dial 8+011, country code, city code, and telephone number. For international calls using a calling card, dial 8+00, the operator will connect you to an international operator.
Toll-Free
Dial 8 + 1 + area code + 7-digit number
Relay Colorado
Relay Colorado is a statewide service that connects standard (voice) telephone users with Deaf, Hard of Hearing, DeafBlind, Speech-Disabled, or Late-Deafened people who use Teletypewriter (TTYs) or Voice Carry-Over (VCO) phones.