Both xmodem and ymodem repeat the initial packet of a transfer even though the initial packet is acknowledged. In the case of xmodem, packet sequence 1 is sent, acknowledged by the receiver, and then sent again by tera term. In the case of ymodem it will be packet sequence 0 with all the file info that is sent, acknowledged by the receiver, and then sent again as if the receiver had NAK'd it.
Tera Term
Both xmodem and ymodem repeat the initial packet of a transfer even though the initial packet is acknowledged. In the case of xmodem, packet sequence 1 is sent, acknowledged by the receiver, and then sent again by tera term. In the case of ymodem it will be packet sequence 0 with all the file info that is sent, acknowledged by the receiver, and then sent again as if the receiver had NAK'd it.