Enabling CTCSS on TM721E

W7	TSU-6	Notes
8:ET	10:ET
7:DT	9:DP	Data
6:CT	8:CP	Clock
5:SDO	7:SDO	Serial data out
4:E	6:TO	TX Out
3:5C	3:5C
2:CI	2:CI
1:E	1:E	Ground
/	4:CO
/	5: PTT

SC(K): The clock pulses that the master can use to enable/disable devices.

In models with the CTCSS cable (A-models), there is a 33k resistor between E (GND) and TO when the CTCSS unit is not inserted. When the unit is installed, then TO in the CTCSS unit goes to VR1 which is a 33k-ohm variable resistor.

Pitch is the distance between pins.
Common one or two rows pin headers are .1” (2.54mm)

http://tech.mattmillman.com/info/crimpconnectors/