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During the initial installation of the VNS, Cisco strongly recommends that a modem be attached to the serial port and configured to auto-answer calls from our Product Support. By dialing in, Product Support can access the VNS remotely and resolve potential problems. An optional Motorola V.34R Modem can be purchased from Cisco. (For initial trials, the modem is required.)
This setup prepares a modem attached to the VNS to answer a call from Cisco's Product Support. You should arrange to work with Cisco Product Support to initially set up and test the modem for dial-in operation (i.e., auto answer). Cisco must record the telephone number for dialing into the VNS.
The port on the VNS should be factory-configured for 9600 bps and VT100 mode. Table E-1 lists the modem interface requirements.
| Parameter | Requirement |
|---|---|
| VNS Port | Serial port, A/B (Terminal) |
| Code | Standard 8-bit ASCII, 1 stop bit, no parity |
| Interface | RS232 DCE |
| Cable | 25-pin straight through cable |
| Phone Lines | Dedicated dial-up business telephone line for ISC-to-VNS modem connection |
| Data Rate | All standard asynchronous data rates from 300 to 19200 bps, independently selectable |
| Supported Modems | Motorola Model V.34R 9600 baud modem |
There are two procedures to be performed before Product Support can dial into the VNS:
These procedures are for a typical connection. Refer also to the Modem User's Guide.
Typically the serial port on the VNS-AC or VNS-DC is factory-configured for 9600 bps and VT100 mode. If it is not, you can configure the serial port (A/B [Terminal]) as follows:
Step 1 Login to the VNS as superuser (i.e., root).
Step 2 Edit the /etc/ttytab file as follows:
ttyb "/usr/etc/getty D9600" dialup on remote
Step 3 Check to see if getty is running for ttyb by entering:
ps -aux | fgrep getty
Step 4 Note the process ID so you can kill it and restart the getty.
Step 5 If a getty is already running for the specified port, find its process id, then issue:
kill -9 <process ID>
Step 6 Restart init by entering:
kill -HUP 1
Step 7 This command restarts the new getty.
To connect and configure the modem for dial-in operation, follow these steps:
Step 1 Connect power to the modem.
Step 2 Temporarily attach a terminal to the modem EIA port, using a straight-through cable. The modem's EIA port will automatically match the 9600 bps setting of the terminal.
Step 3 Configure the modem for 8 bits, no parity, and 1 stop bit.
Step 4 Enter the commands listed in Table E.2 to set up the modem for proper operation.
Step 5 Disconnect the terminal and connect that end of the cable to the VNS port (A/B [Terminal]). (The other end remains connected to the EIA port on the modem.)
Step 6 Connect the modem to the phone line.
Step 7 Ask the Cisco Product Support to test the operation of the dial-in modem.
| Step | Command | Function |
|---|---|---|
| 1 | AT&F&W | Reset to factory default and save. |
| 2 | ATS0=1 | Enables Auto-Answer Mode (answer on first ring). |
| 3 | ATL1 | Modem speaker at low volume. |
| 4 | AT*SM3 | Enables automatic MNP error correction. |
| 5 | AT*DC0 | Disables data compression. |
| 6 | AT*FL0 | Disables XON/XOFF flow control. |
| 7 | AT&S1 | Sets DSR to "normal". |
| 8 | ATE0 | Disables local character echo. |
| 9 | ATQ1 | Disables result codes. (Modem will appear "dead".) |
| 10 | AT&W | Saves current configuration settings in non-volatile memory. |
Not all of the modem EIA leads are supported by the VNS. If a Hayes modem is used in place of the MotorolaV34 Modem, configure the Hayes modem using the following AT commands:
| DCD - On | AT&CØ |
| DTR - On | AT&DØ |
| DSR - Normal | AT&S1 |
| CTS - ON when connected | AT&R1 |
| ATSØ=1 (answer on first ring) |
When the system is up, Cisco Product Support will be able to dial in to the VNS and login as any other user on the system.
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