Motorola P880 Manuale Utente

Cajun P880 Routing Switch Installation Guide 

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In order to use the serial console port as a PPP console, you must 
connect a modem to the switch. When you use the specified serial 
cable and connectors, the switch will convert the normal DCE 
interface to a DTE interface that is used by modems.

When the switch is configured for PPP mode, it will periodically 
send the modem config string from the serial console port. This will 
synchronize the baud rates between the modem and the console 
port and configure the modem to operate with the switch’s DTE 
interface.

The switch does not use any output signals except for TXD. It uses 
the DTR (converted to DSR by the specified cable and connectors) 
input connected to the modem DCD output, to detect that the 
modem is connected. It supports XON/XOFF flow control (or none).

To connect a modem:

1. Attach a DB25M-RJ45 (P/N 38210003)connector to the modem.

2. Attach the DB9M-RJ45 MDCE connector to the switch’s serial 

console port on the front panel of the switch.

You can reconfigure the console serial port as a PPP Console to 
support a dial-in PPP connection using a modem.

* Note:  The lack of an IP address for the PPP serial interface 

causes the switch to immediately return to sending the 
modem configuration string. Typing TTY will re-access 
the CLI login prompt.

Modem

Cajun Switch

DB9M - RJ45

MDCE

DB25 M - RJ45

P/N 38210003

Typical Connection between Cajun

Switch and Modem

Pin 2 - TXD
Pin 3 - RXD
Pin 4 - DTR in
Pin5 - GND

Pin 2 - TXD
Pin 3 - RXD
Pin 7 - GND
Pin 8 - DCD out

pin 6 - NC

pin 20 - DTR in