File Transfer Protocols
CommStudio includes robust, time-tested implementations of the XModem, YModem, and ZModem file transfer protocols.
Each protocol implementation has been proven to interoperate flawlessly with a very wide variety of systems, ranging from mobile devices to mainframe computers.
YModem (also referred to as YModem-Batch) is a variation of the XModem protocol that adds three important enhancements:
- The filename is transmitted, making it easier for systems to distinguish the different files that are transferred.
- The file size is transmitted, overcoming XModem's limitation of having to pad the file to the next multiple of the block size.
- The block size is 128 or 1024 bytes, resulting in less overhead when waiting for an acknowledgement of each block.
YModem-G is a variation that does not wait for an acknowledgment after each block. This enhances speed on perfect connections, but requires the transfer to completely terminate if anything goes wrong.
YModem combines simplicity with an essential feature set. If speed is of great importance, ZModem is a better choice.