TAS has received a full investigation report from SingTel Mobile on the cause of the CDMA trial's interference to M1's GSM network on 12 May 97. TAS' earlier investigation on 12 May 1997 confirmed that the source of the interfering signal ...
Singapore, 18 July 1997 | For Immediate Release
TAS has received a full investigation report from SingTel Mobile on the cause of the CDMA trial's interference to M1's GSM network on 12 May 97.
TAS' earlier investigation on 12 May 1997 confirmed that the source of the interfering signal came from SingTel Mobile's CDMA transmission facility at Mount Faber. It has directed SingTel Mobile to conduct a full investigation. Contrary to what SingTel Mobile claimed in its press statement on 14 May 97, SingTel Mobile has now confirmed that there was actual transmission by the CDMA radio base station at its Mount Faber station. The transmission was within the GSM band used by M1's GSM network.
SingTel Mobile's full investigation showed that a factory test memory card, programmed with a GSM frequency meant for its supplier's own factory tests, was mistakenly inserted into the CDMA base station before it was shipped to Singapore. Although the memory card was subsequently removed, the programme of the card was already read and stored in the CDMA equipment. This memory card contained data that caused the CDMA base station to transmit at the frequency that interfered with M1's GSM network. SingTel Mobile and its suppliers wrongly believed that since the card had been removed from the equipment, there was no possibility of any radio transmission from the Mount Faber installation.
From the full investigation, TAS has determined that this incident was due to negligence by SingTel Mobile and their failure to oversee the CDMA trial to ensure such interference does not occur. By this act, SingTel Mobile has infringed Section 29(1)(a) of the TAS Act 1992. TAS has thus decided to impose a fine of $5000 which is the maximum fine for general breach of TAS' regulations.
To prevent future occurrences, TAS has directed SingTel Mobile to put in place appropriate procedures and safeguards to ensure that their network will not cause interference to other operators' networks. Until such time that TAS is satisfied that SingTel Mobile has put such measures in place, the suspension of SingTel Mobile's CDMA trial remains.