10
HIGH SPEED SHM-B ASYNC AND CARD
on the High Speed SHM-B Async. The High Speed
SHM-B Async at the remote end of the line will sense
this and raise its CD lead (pin 8) when it is
configured as a DCE device.
If the remote High Speed SHM-B Async is
configured as a DTE device, it raises its DTR lead
(pin 20) when it senses an active driver circuit on
the High Speed SHM-B Async at the other end of
the line.
X-ON/X-OFF M
ODE
(J
UMPER
W2
IN THE
B-C [D
ISABLED
]
P
OSITION
)
If X-ON/X-OFF characters are used for handshaking
control, rather than hardware logic levels, move
jumper W2 to the B-C or Disabled position.
Typically, units that use software X-ON/X-OFF flow
control do not want RTS to affect DCD on the
remote High Speed SHM-B Async. Moving jumper
W2 to the B-C position disables the RTS/DCD
relationship. The only thing that will force DCD low
with the jumper in the Disabled position is the
absence of power at either High Speed SHM-B
Async, or a broken twisted-pair wire.
