Remote Processing RPC-210 - Manual (Page 13)

SETUP AND OPERATION SECTION 2
Page 2-7
5. Receiving a sign on message and can't enter
character s.
Check U9, pin 14 for at least -6 volts with the serial
cable connected to the PC . W hen it is near 0 volts,
the terminal or PC ' s Txd line is not connected.
W h e n y o u p r e ss a ch a r ac t er o n t he te r m in a l o r P C ,
you should see the voltage go positive on the
oscilloscope.
If all of this fails, call technical sup port listed in
SECT ION 1.