Black Box MD885AE-R2 Modem User Manual


 
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Modem 34336
After you select UP or DOWN, the LCD will automatically switch to the EIA
status screen so you can see the result of the rate-change request (i.e., the
current data rate, which is displayed in the lower left corner of the EIA status
screen). However, if the Modem has reached the minimum or maximum
speed, it will not switch to the EIA status screen.
NOTE
A request to increase the data rate may result in no change in the data
rate if the signal quality is poor.
If you manually initiate speed renegotiation with RRP enabled, the modem
will automatically renegotiate the speed (again) after four seconds. If the
originate modem attempts to negotiate a rate that is lower than the minimum
rate setting of the answer modem, the answer modem will disconnect (GSTN
cleardown).
4.11 V.13 Operation
The Modem can be configured for CCITT V.13 operation (which emulates
half- duplex operation) for either point-to-point or multidrop applications.
(The correct options for these applications are identified in Chapter 2.) The
Modem normally operates in full duplex; however, some applications (such as
certain network environments) may require control of a remote CD signal by
a local Request to Send (RTS) signal. V.13 operation allows local RTS control
of a remote CD signal without actual ON-OFF switching of the modem
carrier.
The following paragraph explains how the Modem responds to RTS signals
when it is configured for V.13 operation.
When RTS is raised HIGH by the terminal, the V.13 ON PATTERN is sent.
The Modem then raises CTS and data can be sent. When RTS is brought
LOW, the V.13 IDLE PATTERN is sent, and the Modem drops CTS. (If V.13
TX is enabled but the Modem's data pump is not ready to send, i.e., if it is
training or retraining, raising RTS causes CTS to be raised, but the V.13 ON
PATTERN is not sent.) When V.13 RX is enabled, CD turns ON if the V.13
ON PATTERN is detected; CD turns OFF if the V.13 IDLE PATTERN is
detected or if the Modem retrains, loses carrier, or is reset.
MAIN MENU <3>
RESET RATE
12
3
RATE
DOWN UP
12
3