Technical Information; Xl Error Messages - Husky MP2500 Manual

14.6.2 Technical information

The XMODEM protocol is a block-oriented error-checking protocol in the
public domain, which uses checksums or, optionally, CRCs for error-
checking. It can be used for text or binary files and is widely supported. XL
uses standard XMODEM with checksums.
XL uses COM2 on startup.
When the user initiates communications (press E) on the Active
MP2500, it sends a POLL to the host, then waits for a configurable period
(/Pnn parameter, default 10 seconds) before sending another POLL. If there
is no response to 5 POLLs, the download will fail with an error message
(see section 14.6.3).
XL uses checksums to check received blocks. If a received block is
corrupted, XMODEM will request it 5 more times (by sending a NAK) before
reporting an error to XL (see section 14.6.3).

14.6.3 XL error messages

The following error messages may be displayed while using the XL utility:
Communications Errors:
Communications Timeout Error
The connection has probably failed or has never been made. Check
whether the host has hung up (modem) or cable has become disconnected
(direct connection). Check that the host is on-line.
Operator Aborted
You have pressed C to cancel downloading.
Packet Sequence Error
A block has been received out of sequence, eg due to bad line noise.
Check the line (modem) or cable (direct connection).
Xmodem Checksum Error
A corrupted block has been received five times. Check the line (modem) or
cable (direct connection).
Chapter 14: Using Communications 155