Cisco Systems, the largest U.S. network equipment maker, said investors holding 9.37 percent of Norwegian videoconferencing company Tandberg's shares had accepted its tender offer.

Cisco said on November 9 it would extend a 17.2 billion Norwegian crown ($3.1 billion) offer to November 18, but the terms and conditions of its 153.5 crown a share offer would remain unchanged until then.

Cisco said on Tuesday it would announce soon after the extended offer period ends whether the 90 percent acceptances condition for the offer has been met, and would evaluate whether or not to withdraw the offer then.

Cisco's president of European markets, Chris Dedicoat, reiterated that the offer was fair, in Cisco's view.

It's too early to talk about that, he said when asked by Reuters via video link what Cisco would do were it to be unsuccessful in its bid. We believe we've offered a fair price, he said.

Analyst Tore Tonseth of Argo Securities said: This confirms what we have believed for a while... the big majority wants to wait and see how this develops. There's no point in accepting, when you see that 20-30 percent of shares are not accepting.

Shareholders representing 30 percent of Tandberg shares have publicly said they would oppose the offer, demanding more money from Cisco.

Most analysts expect Cisco to sweeten its bid.

Ole Joergen Roed of First Securities said: I think it's more likely that Cisco will increase the offer than that they will walk away. Tandberg at 153.50 is a very good deal, especially for Cisco, which can extract synergies.

They will have to go to at least 170 crowns, he added.

Tandberg shares were little changed at 152.20 crowns by 1449 GMT, outperforming a 1 percent weaker DJ Stoxx European technology index .SX8P.

($1 = 5.596 Norwegian crowns)

(Additional reporting by Georgina Prodhan in London; writing by Tarmo Virki; editing by Greg Mahlich and Simon Jessop)