Past change to telecommunication-concession contracts has come back to haunt the industry's big three.

The industry is always a source of spice, and the latest saga buzzing is allegations levelled by Total Access Communication (DTAC) and True Move at Advanced Info Service (AIS) for unfair practices.

The two cellular operators made the allegations to the National Telecommunications Commission and the Information and Communi-cation Technology (ICT) Ministry.

Specifically, they claim AIS benefits from special support from its concession-owner TOT.

They claim that in 2001 TOT permitted AIS to share prepaid-call revenue at a flat rate of 20 per cent for the remainder of its contract. Revenue-sharing was previously paid at a rising incremental rate.

They added that TOT had waived access charges for AIS but not its two main competitors.

Access charges are paid when a call needs to be connected to a different network. This is done using TOT equipment.

The root of all this is back in 1990 when AIS and DTAC were first granted concessions from TOT and CAT Telecom respectively.

TOT, which owns both domestic fixed-line and mobile-telephone networks, allowed AIS to be the sole private cellular provider before CAT was given government clearance to grant a concession to DTAC.

CAT owned no telephone numbers, so it created its own for DTAC, bypassing the TOT system. When it could no longer supply more numbers to DTAC, DTAC had to go to TOT.

As a result, TOT asked DTAC to pay for numbers and pay an access charge at a flat rate of Bt200 per subscriber per month.

Later DTAC sought a reduction of this to Bt178 per user per monthly. This request was granted on the condition DTAC shared revenue with TOT.

In 2001 TOT asked AIS to pay a flat rate of 20 per cent of prepaid-call revenue throughout the rest of its concession period. AIS argued it deserved the reduction because in the same year DTAC access charges were set at 18 per cent of monthly prepaid-call revenue, a change from the Bt178 user fee.

TOT explained that the cut in AIS revenue sharing had been granted on the condition that AIS reduced call rates.

Recently a former advisor to the House telecoms committee told the Assets Examination Committee this reduction would cost TOT Bt83 billion throughout the remainder of the concession period.

AIS won a 25-year concession from TOT in 1990. Under the original contract, AIS had to share prepaid-call revenue with TOT on an incremental basis. This started at 15 per cent between 1991 and 1995 and rose to 20 per cent between 1996 and 2000, 25 per cent between 2001 and 2005 and 30 per cent between 2006 and 2015.

For example, AIS was required to share the greater of either Bt12.9 million or 15 per cent of revenue in the first year followed by either Bt34.5 million or 15 per cent in the second year.

Revenue-sharing rose to either 20 per cent of prepaid-call revenue or Bt253 million in the sixth year. In 2001 AIS had to share the greater of either Bt676 million in or 25 per cent of revenue. This rises to Bt1.235 billion or 30 per cent of revenue in the 16th year and Bt1.46 billion or 30 per cent in the contract's 20th year.

AIS claimed last week that DTAC had saved Bt47.76 billion from a reduction to 18 per cent in its access charges and that that would rise to Bt200 billion in 2018.

AIS also wondered if DTAC selling two segments of the 12.5MHz bandwidth of its 1,800MHz spectrum to Wireless Communication Services (WCS) and Digital Phone (DPC) of Samart Corp amounted to the sale of a national asset.

DTAC said it had sold the bandwidth to CAT in 1996 and that CAT had later given it to WCS - now known as True Move - and DPC, an AIS subsidiary.

AIS and DTAC are in arbitration over a dispute involving DPC. After the bandwidth sale to WCS and DPC these companies signed a network roaming deal with DTAC in 1997.

DPC has to pay Bt5.4 billion in roaming charges to DTAC between 1998 and 2005, but DPC stopped paying these in 2001 when DPC was taken over by AIS parent Shin Corp and DPC started roaming on the AIS network.

DTAC claims DPC owes it Bt4.739 billion in overdue fees.

A telecoms source said all the problems in the industry stemmed from continued political interference in state agencies.

He added that ICT Minister Sitthichai Pookaiyaudom had recently said operators complained about unfair competition but did not dare admit they had all made huge profits along the way.