Mobile phone company officials are due for a joint press conference Tuesday morning during which they are expected to state a collective positionon government’s decision to tax phone talk time.Joy News sources say the operators plan to request a review of the government proposal.The proposed tax on phone talk time, announced in the 2008 budget, is being opposed by various social and pressure groups. But government says the tax is a measure to rake in revenue lost to the state because importers of handsets evade duty.