TITLE: GCN CIRCULAR NUMBER: 34990 SUBJECT: GRB 231111A: GECAM-C detection of a long burst DATE: 23/11/12 01:02:21 GMT FROM: wenlongzhang2018@163.com Wen-long Zhang, Shaoli Xiong, Yue Huang report on behalf of the GECAM team: GECAM-C was triggered by a long burst, GRB 231111A, at 2023-11-11T14:17:19.850 UTC (T0), which was also observed by Swift/BAT  ( GCN 34981) . According to the realtime alert data, the GECAM-C light curve shows roughly two peaks with a total duration of ~30 sec (20-1000 keV). The time-averaged spectrum could be adequately fit by a Band function with a flux about 3.36E-7 erg/cm2 in 20-1000 keV. We note that these results are based on realtime alert data and thus very preliminary. Refined analysis will be reported later. Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM) mission originally consists of two microsatellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).