I have done connections as below for JTAG connector from 10 pin to 20 pin lauterbach connector of LA-7844 debug cable
10 pin 20 pin ARM Standard JTAG
1 VCC 1 VREF-DEBUG
2 TMS 7 TMS
4 TCLK 9 TCLK
6 TDO 13 TDO
8 TDI 5 TDI
10 RST 15 RESET
3,5,7,9 GND 4,6,8,10,12,14,16,18,20 GND