Black Box MD885A-R3 Modem User Manual


 
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Modem 34336
The Test Mode (TM to EIA) option is available for all modes. It controls
pin 25, the test mode (TM) indicator, on the RS-232 interface connector.
• NORMAL — TM output is high (active) only during test modes.
• TRUE — TM output is high all of the time.
3.3.7 M
ODEM
S
ETUPS
The options listed below, through RTS-CTS DELAY, are available through
the MODEM SETUPS screens.
The Carrier Detect option is available for all modes. It selects the carrier
detect level. To make a selection, first select either LEASED or DIAL from the
CARRIER DET. LVL screen, depending on your application. The appropriate
carrier detect level screen is displayed.
• For leased-line use — the carrier detect level can be set for 43, 33 or 26
dBm. The default setting is 26 dBm.
• For dial-line use — the carrier detect level can be set for 51, 41, or 34
dBm. The default setting is 51 dBm.
The Transmit Level option is available for all modes. It controls the modem’s
transmission level. To make a selection, first select either LEASED or DIAL
from the TRANSMIT LEVEL screen.
• For leased lines — the transmission level can be set between 0 and -15
dBm, in 1-dBm steps. The standard setting is 0 dBm. (Use pushbuttons 1
and 3 to select the desired transmission level.)
• For dialup applications — the transmission level for dial lines can be set as
either programmable, if you are using RJ-45S connectors, or permissive,
fixed at -10 dBm +/-1 dBm, which is the most common setting.
The Signal Quality option is available for all modes. It sets the threshold for
the ER (error) indication during normal operation. You can choose either
"10 3", one error in 1000 bits, or "10 5", one error in 100,000 bits. Signal
quality (along with carrier detect) also controls the threshold the modem uses
as a criterion for entering the Leased Line Auto-Recovery mode.