The Pacific OTC (POTC) is an Over the Counter information system and match trading platform  for shares and debt instruments. POTC has global access, operates through securities dealers  entering buy and sell inquiries in the system when they have customers who want to buy or sell  shares in a company listed on one of the Pacific OTC tiers. Other securities dealers can see these  bids and asks on their computer monitors and can contact the securities dealer or contact Pacific OTC to express interest on a possible transaction.  When the trade comes about, the buying securities dealer then registers the transaction with the Pacific OTC. To participate on POTC a broker or dealer needs only to register with Pacific OTC before they can enter an order or receive information.

More information on the Pacific OTC can be found here