The current WEB Access Library has been written as a single threaded module, which means the data conversation must be complete before control is returned to the ESL application. Given that communication over the Internet can be slow, typically taking a number of seconds to complete the operation, your ESL application will stop responding for this time. So far, no ESL Clients using the ESL Access library have experienced problems with this synchronous approach. If you need to maintain the responsiveness of your ESL application, then you could develop a DDE server application in ESL to perform the calls to the WEB access library. As an alternative, contact the ESL Help Desk to discuss your requirement, as we are always pleased to incorporate improvements in our product.