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1.8
Modem LED Indicators
The MT2834MR6 has five LED indicators per modem:
TD Transmit Data. This LED blinks when data is being transmitted, on for a space, off for a mark. The
state of this LED matches that of the TD circuit on Pin 2 of the RS-232C interface.
RD Receive Data. This LED blinks when data is received, on for a space, off for a mark. The state of
this LED matches that of the RD circuit on Pin 3 of the RS-232C interface.
CD Carrier On. This LED lights when a valid carrier tone has been detected.
Speed Speed. This LED blinks at different rates to indicate the speed of the data connection:
Data Rate (bps)
12000 or less
14400 or 16800
19200 or 21600
24000 or 26400
28800 or more
OH/OOS Off Hook/Out of Service. This LED lights when the modem is off hook, which occurs when the
modem is dialing, online, or answering a call. The LED flashes when the modem is in the busy-
out or out-of-service state.
Note: The PS4800 modem rack power supply has one LED that indicates the presence of all supply voltages.
1.9
Busy Switch
The MT2834MR6 has six two-position Busy switches on the front panel. Each switch can be used to create a
"busy-out" (OOS) condition for one of the six on-board modems (i.e., modem A, B, C, D, E, or F).
To place a modem in the Busy condition, move the appropriate Busy switch to the right. The selected modem
goes off-hook, its OH/OOS LED begins to flash, and incoming calls to this modem get a busy signal. If you
suspect a problem with a particular modem, you can use the Busy switch to have an optional device (such as
a "hunt group") that looks for a non-busy line to perform a rollover to the next available modem while you
check the status of the Busy modem.
Note:
The MultiModemManager can perform the same function using software.
LED State
Off
Slow blink rate
Medium blink rate
Fast blink rate
On
Chapter 1 - Introduction
15
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