[Heathkit] Heathkit DX-100 question

[Y S Lee]

Hello;
 I am studying DX-100 schematic to acquire knowledge to build an AM-CW 
transmitter of my own design. Looking through it, I could not understand how to synchronize the 
TX frequency with a matching RX. Usually TX has a SPOT function to monitor
the TX freq with an RX. DX-100 does not seem to have that.
Another question is how to switch between SEND- RECEIVE. I could not find this
switch at a DX-100 photo.
de HL1FB/WW6N