I asked Ewen about this issue and he allowed me to post his response as a followup for the benefit of everyone. Cheers, Andrew Ewen Responds: ==== andrew.roughan@writeme.com (Roughana) wrote in message: >> I have no idea if Spectrum's Zmodem was designed to be used with >> TCP/IP or not. The problem with using the Internet for X/Y/Zmodem is that there might well be delays that arise in the middle of the data packets being received. As the integrity of X/Y/Zmodem is primarily designed round timeouts, this causes problems and so slow transfers. You can of course remove the timeouts, but if a piece of data is lost, the download will never complete. If you increase the timeouts, the process may well take far too long to complete. Basically X/Y/Zmodem are not best suited to the Internet, unless you have a good fast and loss free path to your ISP. FTP is better, as it does not involve timeouts. >> Spectrum's handling of special characters passed across the Telnet >> connection with Zmodem Spectrum handles the full 8-bit character set for Telnet, but this assumes the host is also supporting the 8-bit path. Problems with Zmodem under TCP/IP I suspect will all come down to the character timeout factor. Kermit is a better solution if FTP cannot be used, as long as the host that is connected to can handle full 8-bit Kermit, with extended packets, and or sliding windows. It is then faster than Zmodem. Unfortunately many ISPs cannot handle the full Kermit implementation. I do know that ProTerm Mac does not have the same problems with Zmodem and a Telnet connection, but there may well be other factors at work with that program running on a Mac. From what I remember some years ago when this problem was first reported, my tests with the timeouts seemed to give the most conclusive reasons as to why it did not work well with Spectrum. I do though remember that I used to Telnet to Genie through a Compuserve connection using Spectrum, and Zmodem worked just fine with that. I (and you) would be connecting through a link that had a long delay compared with those in the States. The turnround response of packet and acknowledgement can also be a factor I think... Cheers - Ewen ====