Anonymised Call Detail Records of Saratov State University Telephony

Anonymized Call Detail Records from a Corporate Telephone Network (Saratov State University) Data source The dataset originates from the IP‑telephony system of Saratov State University (SSU), covering the period from December 2022 to March 2026. The raw database includes 467 IP subscribers with internal and external numbers and a log of 534,323 call records. Preprocessing Self‑calls and records with non‑conforming number formats (internal: 4‑digit, external university: 6‑digit, city and mobile: 10‑digit) were removed. All internal numbers were changed by external. After filtering, 302,201 calls remained. All phone numbers were anonymized using HMAC‑SHA256 hashing, ensuring irreversible transformation while preserving the network topology. Dataset Structure The final version contains 302,201 records about calls. Each record includes: id – UUID4 of call; calling_station_id – hashed caller identifier; calling_station_type – type of caller (types described below); called_station_id – hashed callee identifier; called_station_type – type of callee; time_start – call start time (UTC), maybe NULL if time is unknown; time_end – call end time (UTC). The types of correspondents are the following: ip_sgu – correspondent of IP-telephony of the university; other_sgu – correspondent of other telephony of the university; external – not university correspondent (e.g. mobile or city phone). The other_sgu category consists of telephone numbers obtained from the official SSU website that are not part of the IP‑telephony system. Call records are available only when at least one participant is an IP‑telephony subscriber (ip_sgu). Consequently, calls between two other_sgu numbers are not recorded. The table below presents the call counts for each combination of caller and callee types. Caller / Callee ip_sgu other_sgu external ip_sgu 24,980 42,918 100,881 other_sgu 38,921 0 0 external 94,501 0 0 The time of call beginning is known in 82.1% records, while the end time is present in all records. Times are given in UTC format. Supported by the Ministry of Science and Higher Education of the Russian Federation (project No. FSRR-2026-0003).