1 Introduction
6

MT5600BR-V92 User Guide

LED Indicators
The MT5600BR-V92 has ten LED diagnostic indicators.
RCV XMT CO 56 33.6 14.4 OH DTR RI ERR
RCV - This LED blinks when data is being received, on for a space, off for a mark. The state of this
RCV LED matches that of the RCV circuit on Pin 3 of the RS232C/V.24 interface.
XMT - 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 XMT circuit on Pin 2 of the RS232C/V.24 interface.
CO - This LED lights when a valid carrier tone has been detected.
56 - This LED is lit when the modem connects using V.92 protocol. The actual connection speed
depends on ISP server capabilities and line conditions.
33.6 - This LED is lit when the modem is connected at 33,600 bps. Note that when both 33 and 14
LEDs light, modem is in 16,800 to 33,600bps mode of operation.
14.4 - This LED is lit when the modem is connected at 14,400 bps.
OH

- This LED is lit when the phone line is

“off hook”

. This occurs when the modem is dialing, on
line, or answering a call. The LED also flashes when the modem is pulse dialing in the
Command Mode.
DTR - When the DTR LED is lit, the modem is permitted to answer an incoming call. When DTR
goes off, a connected modem disconnects if dependent on DTR. The state of this DTR LED
matches that of the DTR circuit on Pin 20 of the RS232C/V.24 interface.
RI - This LED is lit during the ringing interval as an incoming call is received.
ERR - When the ERR LED is flashing, the leased line is down and the modem is in self-test mode
has failed. When ERR LED is on, this indicates the modem is in an out of service (

OOS

) state.
When the modem is out of service, it is busy to incoming calls.