2.10 CASCADING OR CONCATENATION
The DMM-4DC supports cascading by utilizing DB-25 Male-to-Male straight through shielded
cables.
Subchannel Port 1
should be used as the concatenation port.
2.8
MANUAL DTE/DCE REMOVAL
The DMM-4DC incorporates circuitry that will (when enabled)
manually
remove a streaming
terminal from service. A streaming terminal is defined as a terminal that has RTS continually
high
. With Anti-streaming disabled, the associated streaming DTE will
NOT
illuminate a
Yellow LED on the front of the MSD. If the automatic anti-streaming circuitry is disabled and a
streaming condition occurs, the other DTE devices will be blocked from accessing the
communications link. To correct this condition, simply push the associated push-button switch
for the subchannel that is streaming. All other DTE's will now continue to be serviced by the
DMM-4DC. However, you still need to fix the offending DTE or DCE device that has RTS or
DCD continually raised.
2.9
UNEXPLAINED STREAMING TERMINALS
Many different types of terminals have been manufactured over the years. A typical problem is
unexplained lockup or lockout problems. The most common cause is when, four terminals are
running just fine and when one of the terminals is powered down, the remaining terminals are
locked out of service. This may be explained by a missing or incorrect Termination Resistor that
has been overlooked by your terminal manufacturer. This is the main reason that Anti-Streaming
circuitry has been designed into the DMM-4DC and we encourage the user to take advantage of
this feature. An additional feature is a 4.7k Pull Down resistor tied to the RTS or DCD control
leads.
DMM-4DC OPERATIONS MANUAL
Page 4
D
M
M
D
M
M
MODEM
CONNECT TO MASTER PORT
CONNECT TO PORT 1
DB-25 CABLE
CASCADING DIAGRAM
OR F.E.P.
