Telkom has once again renewed its cautionary notice to shareholders, informing them that it remains locked in negotiations with rival MTN about a deal.

“Shareholders are advised that Telkom and MTN South Africa remain in discussions regarding the potential extension of their existing roaming agreement to include bilateral roaming and outsourcing of the operation of Telkom’s radio access network, which if successfully concluded may have a material effect on the price of Telkom’s securities,” Telkom said.

In mobile communications, the radio access network is the wireless component of an operator’s network through which consumers connect to the core network. It involves the sections of the network that connect end-user devices to wireless base station infrastructure.

“The parties will update shareholders as soon as they receive the appropriate legal and regulatory approvals,” Telkom said.

The two companies have been locked in talks for almost 18 months. TechCentral first broke the news in November 2013 about the discussions between them, with Telkom formally revealing it was in talks with MTN in a statement to shareholders in March 2014.

MTN and Telkom may be pursuing a deal, at least in part, because of Vodacom’s offer to buy Neotel. Neotel has an extensive fixed-line infrastructure and IT assets, including data centres, and, crucially, also has access to radio frequency spectrum that can be used for building next-generation 4G/LTE networks.