Furuno CSH-23 - Manual (Page 92)

13-4
Gray test
This test checks for screen distortion. To escape from
the test reset the power.
SIO test
This test checks for proper communication between
the display unit and transmitter unit, and requires a
jumper plug. To escape from the test reset the power.
GRAY TEST
, Q, Q
Figure 13-7 SIO test
Figure 13-6 Gray test
SIO TEST
DRAW
IF
PISO
PIF
SIO
SIO
SIO1
SIO2
SIO1
= OK
= OK
= OK
= OK
= OK