Tahoe 684, User Manual

2

2.

Interfaces

Following connectors are found on the rear panel of the modem:

2.1.

G.shdsl

It is a 8-pin RJ-45 connector used to connect the leased line. The 

pinout is similar to an EIA-568 (Cat5) connector. Subsequent lines may 
be interchanged between modems - that condition will be automatically 
detected. The polarization of a line is not important.

2.2.

Serial console

The RS-232 serial console is used for modem management. It has 

a DB9/M connector and works as a DTE, i.e. a null-modem cable should 
be used to connect it to a PC. Three lines (bolded) are sufficient. Terminal 
settings are 9600 bps, 8 data bits, 1 stop bit, no parity, no handshaking.

3

After connecting the console to the PC and running a terminal 

software, user has the same access to the modem functions, as through 
a telnet connection (see chapter 4).

2.3.

FastEthernet

The FastEthernet interface

 is used to connect the modem to the 

Local Area Network. It may work at speeds of 10 Mbps (10Base-T) or 100 
Mbps (100Base-T), in either full-duplex or half-duplex mode. The mode 
of transmission is selected automatically, although it may also be fixed 
using appropriate telnet commands.

Modem should be connected to a Ethernet switch or a hub using a 

straight patch-cord or to a PC, a router or an uplink port in a switch using 
a crossed-over one. After connecting a LED named “LAN Link” should be 
lit.

®

In the 

Tahoe  68

4

 modem 

the FastEthernet interface has 

following status LEDs: 

¡

LAN Link  -

 lit, when modem is connected to a LAN

¡

LAN Act

- LAN activity, blinks when data is sent or received

¡

10/100M

  - LAN connection throughput - lit, when 100 Mbps 

connection speed is negotiated

On the right two WAN status LEDs are present, blinking when data 

is, respectively, received from or sent to the DSL line:

¡

WAN Rx- 

WAN Receive

¡

WAN Tx - 

WAN Transmit

2

2.2

Pin

Name

1

DCD

2
3

4

5

6

RXD

TXD

DTR

GND

DSR

Description

carrier detect, transmission readiness signaling

data received from the PC
data sent by the modem to the PC

active, when the PC is switched on

signal ground

active, when the modem is switched on

7

RTS

used by the PC to inform that is has data to send

8

CTS

used by the modem to permit data transmission

9

RI

ring indicator (signal used in telephone modems)

G.shdsl

serial

console

LAN

(FastEthernet)

power
switch

power

connector

O

I

2.1

Pin

Tahoe 684

1
2
3

4
5

line 3
line 2

7

6

8

line 1
line 1

line 2
line 3
line 4
line 4

2.3