JOHANNESBURG (Reuters) - South Africa's rand firmed against the dollar on Friday ahead of an expected announcement on merger talks involving mobile phone firm MTM which could have a dramatic impact on the currency. The rand touched a session high of 7.7425 against the greenback before coming back to 7.7725 by 0639 GMT, still up 0.77 percent from Thursday's 7.8325 close. The rand's gains mirrored those of global equity markets and other emerging market currencies which have firmed on hope the the global economy is set for recovery from its downturn. The market is awaiting news from MTN and India's Bharti, which are in exclusive talks until July 31 over a deal that could lead to a full merger, creating a wireless group with combined revenue of $20 billion. Prospects of foreign currency inflows from a possible merger have helped support the rand in recent weeks. "The outcome of the deal could have an explosive impact on the rand today, especially in the event of a decision to call the merger off," said Alvise Marino, emerging market analyst at IDEAglobal. "We do not see this as a likely option ... yet further delays could hamper appetite for the rand in the short term," he said. The blue chip Top-40 September futures contract was up 0.68 percent ahead of JSE securities exchange's opening at 0700 GMT. Government bonds also firmed, with the 2015 bond yield falling 3 basis points to 8.37 percent and that on the 2036 bond down 3.5 basis points at 8.425 percent. | 
