My PC = CPU Athlon 1800/
Have problem : no connect T28,A2618,A2628 with PC. Try connect with PC - telephon turn on. May be wrong cable?
I try another cables( pin out) - problem no solved.
I used MAX232 with 5V.
Try another computer (IP166) - result one.

WBR, SergeyP.

Try this. Remove battery, start program, issue command (ex. read flash), immediately insert battery. U may have to press "NO" after inserting battery. This worked for me with several models.

Problem is solved!
Will be need is MAX3232 witl levels 3V.

Thanx for all.