A joint venture between the Royal Bank of Scotland Plc and Banco Santander of Spain has been turned into a serious challenge to Swift, the Society for Worldwide Interbank Financial Telecommunications now that Electronic Data Systems Corp has joined the party, taking an equal 31.66% stake with the two partners in Inter-Bank On-line System Ltd, and Goldman Sachs has come in for 5%. IBOS links four European banks companies at more than 2,600 locations, and now will expand worldwide. The key difference between the IBOS system and Swift is that the latter is interactive rather than unidirectional, providing confirmation of funds transfers in seven seconds, and a queue of banks is said to want to join the system, which uses custom software on MicroVAX nodes and transmits via the BT/Tymnet and Infonet networks.