7318 Troubleshooting

7318 Model S20 Guide and Reference

7318 Troubleshooting

The following troubleshooting information is divided into the following areas:

The troubleshooting information is intended as a guide to help in problem isolation. Some of this information assumes more technical knowledge of the devices or applications involved.

One approach to isolation is substituting known good components or devices for suspect ones, including another 7318 if it is available. This approach is not included in these isolation procedures because the availability of hardware at the installation site is unknown.

In all cases where you are asked to check the cabling or devices, you may replace cables, adapters, devices, null modems, and so forth to help isolate the problem.

To use this section most effectively:

Select the area that covers the problem.
Follow the recommended actions and procedures.

System Checkout Using the Standalone BIOS Console

The following procedure guides you through a full checkout of the 7318, providing a quick test to tell if the 7318 hardware needs to be replaced. The procedure uses the 7318 BIOS console commands to run diagnostic wrap tests on all of the ports on the 7318. If a failure is detected, no Service Request number is generated and you must replace the unit.

Note: Customer Engineers should run this procedure for 7318 FRU isolation. If the 7318 hardware passes this checkout, use the other troubleshooting information and procedures outlined in the previous bulleted list to isolate the problem. The problem may originate from a wide spectrum of hardware and software variables including devices, cables, networks, and configuration parameters.

Prerequisites

An ASCII terminal must be available for the BIOS console.
All ports on the 7318 must be inactive (all users logged off and all applications stopped).
Establish a BIOS console. Refer to "BIOS Console Operation" and "7318 Diagnostics" for a description of the BIOS console and the set, show, and diag commands. To request a BIOS console, perform the following steps:
1. Unplug the 7318 power cord.
2. Connect an ASCII terminal to any one of the 7318 serial ports.
3. Set the terminal to 9600 baud, 8 data bits, one stop bit, no parity.
4. Plug in the 7318 power cord.
5. Type # (pound sign, ASCII 0x23) continually until the console echoes #### (four pound signs).
6. The BIOS should respond with a console header and the > (redirect symbol) prompt.
Enter password privilege mode, using the admin command. Refer to "admin Command" for information on how to use the admin command.

Run the Ethernet Port Wrap

Remove all the Ethernet cable(s) from the 7318, noting the ports (A,T, T-X, I, O) they are connected to for later reattachment.
Note: If the daisy-chain cable is not removed when doing LAN diagnostics, the diagnostic will fail along with any further LAN diagnostics. A reboot of the 7318 is needed to clear this failure.
Attach the AUI Ethernet wrap plug (Part Number 71F1167) supplied with your system to the AUI Ethernet port (labeled "A" on the back panel).
1. Run the Ethernet port wrap test by entering the following commands, noting any error indications that appear:
```
set device lan
set interface 2
diag -w
```
2. Remove the AUI Ethernet wrap plug from the AUI Ethernet port.
Attach the RJ-45 Ethernet wrap plug (Part Number 00G2380) supplied with the 7318 to the T Ethernet port.
1. Run the Ethernet port wrap test by entering:
```
set device lan
set interface 1
diag -w
```
2. Remove the RJ-45 Ethernet wrap plug from the T Ethernet port.
Attach the RJ-45 Ethernet wrap plug supplied with the 7318 to the T-X Ethernet port.
1. Run the Ethernet port wrap test by entering:
```
set device lan
set interface 1
diag -w
```
2. Remove the RJ-45 Ethernet wrap plug from the T-X Ethernet port.
Attach the DB-9 daisy-chain wrap plug (Part Number 65G2382 male) to the O port. This wrap plug is only available with Feature Code 7909. If not used, skip to step 7.
1. Run the Ethernet port wrap test by entering:
```
set device lan
set interface 0
diag -u
```
2. Remove the wrap plug from the O port.
Attach the DB-9 daisy-chain wrap plug (Part Number 65G2407 female) to the I port. This wrap plug is only available with Feature Code 7909. If not used, skip to step 7.
1. Run the Ethernet port wrap test by entering:
```
set device lan
set interface 0
diag -u
```
2. Remove the wrap plug from the I port.
Reattach all Ethernet cables to the 7318.
If there were any error indications, then this procedure has failed. Stop problem isolation and replace the 7318.

Run the Parallel Port Wrap

Remove the parallel port cable or cables from the 7318 connectors (labeled P1 and P2) noting the ports they are connected to for later reattachment.

Attach the parallel port wrap cable (Part Number 65G2381) supplied with your 7318 to the parallel ports.
Run the parallel port wrap test by entering the following commands, noting any error indications that appear:
```
set device lpt1
diag -m
 
set device lpt2
diag -m
```
Remove the parallel port wrap cable and reattach the parallel port device cables.
If there were any error indications, then this procedure has failed. Stop problem isolation and replace the 7318.

Run the Serial Port Wrap

Run the serial port wrap for each serial port, COM00 through COM15 (other than the BIOS console port), on the 7318. Perform the following steps:

Remove the cable from the RJ-45 connector for the serial port to be tested.
1. Install the serial port wrap plug (Part Number 65G2350) supplied with the 7318.
2. Run the serial port wrap test by entering the following commands, noting any error indications that appear. Change the device identifier, com00, to match the port being tested.
```
set device com00
diag -w
```
3. Remove the serial port wrap plug and reattach the serial cable that was connected to the port.
4. If there were any error indications, then this procedure has failed. Stop problem isolation and replace the 7318.
Remove the BIOS console terminal and reattach the serial cable for the port as it was prior to running the procedure in "System Checkout Using the Standalone BIOS Console" on page 12-1.

If any of the diagnostics indicate a failure, replace the 7318.

If there were no error indications, then this procedure has passed. Exit this procedure. If you were referred to this procedure from another procedure, return to the original procedure and continue problem isolation. If you have performed no other diagnostic procedures, load the 7318 from a host on which the 7318 software is installed. Refer to "Front Panel Light Status (Startup and Loading)" if the load is unsuccessful.

System Checkout Using the Service Aid

The following procedure guides you through the operation of the 7318 Service Aid. It performs wrap tests on the 7318 parallel and serial ports, providing a reliable test of whether the hardware is operational. If the Service Aid detects a failure, it may be caused by many different parts of the system. In this case, perform the "System Checkout Using the Standalone BIOS Console" for further problem isolation.

Note: The Service Aid can only be run from a system on which the software is installed and the devices and ports to be tested have been configured. For Model S20 units, the serial ports may not have P10-style ports configured on the system where the 7318 software support is installed. If there are no P10-style ports configured on the Model S20, the Service Aid will not be operational.

Prerequisites

You must have root user authority to run the Service Aid.

Note: Running some of the diagnostics automatically logs off any users on the 7318; thus, the diagnostics should be used carefully.

Procedure

To run the Service Aid, issue the diag command from the AIX command line.
From the first panel, select Service Aids.
From the next panel, select IBM7318 ComNet Server Service Aid.
Select whether you want standard tests, which do not require special plugs, or advanced tests, requiring a serial port wrap plug (Part Number 65G2350) or a parallel port wrap cable (Part Number 65G2381). Press Enter.

The diagnostics run unattended and display their results in the diag command window. At the end of the diagnostics, either RESULT: SUCCESS or RESULT: FAILURE displays. If there is a failure, at least one additional message describing the problem displays. For example, you may also see a message such as Device power-on self-test failed.

Problems with BIOS Console Communication

If you have problems requesting a BIOS console, consider the following symptoms and their possible causes:

BIOS Console Problems
Symptom	Action
Console doesn't echo pound sign.	Verify terminal is cabled correctly.Verify terminal settings (9600/8/1/N).Power-cycle the 7318 and type the pound sign a little later.Try a different serial port.
Pound sign garbled.	Verify terminal settings (9600/8/1/N).
No console header message.	If pound signs echo, try repowering the 7318 and typing the first pound sign faster, (four or more).Try a different serial port.
No Ready light within 20 seconds.	Power-on self-test failed. Replace the unit.

Terminal is Cabled Correctly

If your terminal has a Data Terminal Equipment (DTE) interface, the cable will require a null modem adapter. The cabling must support pins for Transmit Data (TD), Receive Data (RD), and signal ground (TD REF). Refer to "Connector Pinouts" for more information.

Terminal Settings

Verify that the terminal transmits and receives at 9600 baud, with 8 data bits, 1 stop bit, and no parity. Check the emulation mode of the terminal (if applicable) to be sure that the # (pound sign) key you are pressing corresponds to an ASCII pound sign symbol (0x23).

Power Cycle the 7318

Unplug the 7318 and wait 30 seconds, then plug in the power cord again.

Front Panel Light Status (Startup and Loading)

The following procedure targets problems arising during startup and loading.

Familiarize yourself with the following symbols, which are used to reference the light patterns:

0 indicates the light is off.
1 indicates the light is on.
B indicates the light is blinking.

The Valid 10Base-T Light Pattern figure shows how the preceding symbols correspond to the lights on the front panel. In this situation, the 1 1 0 1 light pattern would signify that the power and the ready light are on, the AUI light is off, and the 10Base-T light is on.

Examine the front panel lights, and match them with the patterns in the following list:

0 0 0 0	No power to the 7318. Action: Verify power to the 7318, cycle the power, wait 10 seconds. If the light pattern changes, continue to match the new pattern with those shown in the table below. (This should have no effect on other devices attached to the Ethernet.) Attention: Daisy-chained 7318s will lose their connection if a higher 7318 in the daisy chain is power cycled (for example, power-cycling the second 7318 will end network connection for the third and fourth 7318 in the daisy chain. If the light pattern does not change, replace the unit.
1 0 0 0	The power-on self-test appears to detect a fatal error. Cycle the power, wait 15 seconds. If this pattern persists, replace the 7318.
1 B 0 0	Power-on self-test is complete, 7318 search for load host is in progress. (This light pattern is also seen when the BIOS console is active.) Wait 30 seconds. If lights remain in this state, the 7318 has not found an operational Ethernet interface, or the transceiver attached to the Ethernet port does not support SQE heartbeat. Continue with the steps described below: If the transceiver attached to port A does not support SQE heartbeat or if SQE heartbeat is turned off, move to light pattern 1 B 0 1 or 1 B 1 0. Enable SQE heartbeat if the transceiver supports it. If the 7318 is part of a 7318 daisy chain, then: Check that you cabled the 7318s correctly and power off all 7318s in the daisy chain. Power on the daisy-chained 7318s starting with the first. Refer to "Attaching Multiple 7318s" for information on daisy-chain configuration. Remove the 7318 from the daisy-chain, and ensure it downloads correctly by itself on the Ethernet. If the independent download fails, then continue problem isolation with step 3. If the independent download succeeds, run the procedure described in "System Checkout Using the Standalone BIOS Console" for each 7318 in the daisy-chain, looking for an in/out port (I and O port) failure. Call your next level of support. Check for an Ethernet media problem. Refer to your Ethernet setup/installation guide to check for incorrect cabling, bad termination of the Ethernet, loose connectors, bad cable, down routers, and so forth. Check for an Ethernet interface problem on the host. Refer to your Ethernet setup/installation documentation and look for incorrect definition of the Ethernet interface, host addresses and subnets, bootp configuration (Model S20), Model P10 SMIT panels, and so forth. Check for a host or 7318 configuration problem. Refer to your 7318 installation and configuration documentation, and look for correct setting of network addresses, Model P10 SMIT panels, configuration file setup, and so forth. Other things to try: On any host where the 7318 software is installed: the cnsview -c "explore" command should display all 7318s that are powered up and reachable from the host. On any host where the 7318 software is installed: the cnsview -c "ipxping EthernetAddress" command should display the following response: EthernetAddress is alive where the `EthernetAddress` parameter specifies the Ethernet hardware address on the back of the 7318. Attach a BIOS console and issue the load command. The console will display log messages as the load sequence progresses, allowing you to check for the following: Network addresses Name resolution Service advertisement and response Bootp reply Download image path and file name Ethernet frametype Configuration file path and file name. The degree of progress made in these steps may also indicate where the problem is. Refer to "BIOS Console Operation" and "Logging During Load" for more details. Stop and restart the cnsview daemon and ipx protocol stack by issuing: To STOP: cnsview -c "daemon stop" /usr/lpp/netware/bin/stopnps To START: /usr/lpp/netware/bin/startnps cnsview -c "daemon start" Run the procedure described in "System Checkout Using Standalone BIOS Diagnostics Procedure" . Call your next level of support.
1 B 0 1
1 B 1 0	Load image and configuration file load in progress. Check for an Ethernet interface problem on the host. Refer to your Ethernet setup/installation documentation and look for incorrect definition of the Ethernet interface, host addresses and subnets, bootp configuration (Model S20), Model P10 SMIT panels, and so forth. Check for a host or 7318 configuration problem. Refer to your 7318 installation and configuration documentation, and look for correct setting of network addresses, Model P10 SMIT panels, configuration file setup, and so forth. Other things to try: On any host where the 7318 software licensed program product is installed: the cnsview -c "explore" command should display all 7318s that are powered up and reachable from the host. On any host where the 7318 software licensed program product is installed: the cnsview -c "ipxping EthernetAddress" command should display the following response: EthernetAddress is alive where the `EthernetAddress` parameter specifies the Ethernet hardware address on the back of the 7318. Attach a BIOS console and issue the load command. The console will display log messages as the load sequence progresses, allowing you to check for the following: Network addresses Name resolution Service advertisement and response Bootp reply Download image path and file name Ethernet frametype Configuration file path and file name. The degree of progress made in these steps may also indicate where the problem is. Refer to "BIOS Console Operation" and "Logging During Load" for more details. Run the procedure described in "System Checkout Using the Standalone BIOS Diagnostics" . Call your next level of support.
1 1 0 0	The 7318 has successfully downloaded. The 1 1 0 0 light pattern is valid for: Configuration file processing (five minutes maximum). Ethernet transceivers that do not support the SQE heartbeat. If after five minutes the 7318 is still not operational: Link integrity has been lost. Check the Ethernet connections. Run the procedure described in "System Checkout Using the Standalone BIOS Console" . Call the next level of support.
1 0 1 0
1 0 0 1	Upload in progress. Refer to "BIOS Upload Sequence" for details on the BIOS upload.

Call the next level of support.

1 1 1 0
1 1 0 1	The 7318 is loaded and operational. Problems that persist with this light pattern are likely to be host configuration problems. Check configuration file and Model P10 SMIT panels for incorrect configuration information. Call next level of support.
1 1 1 1	Light test. If temporary, none. If solid, replace unit.
0 X X 1	Invalid Pattern
0 X 1 X	Invalid Pattern
0 1 X X	Invalid Pattern
Other	Invalid Pattern If the 7318 fails the power-on light test but otherwise operates normally, replace the 7318 at your discretion. If the 7318 fails the power-on light test and operates abnormally, run the procedure described in "System Checkout using the Standalone BIOS Console" . Call the next level of support.
Cycling	If the 7318 is cycling through patterns: Load using the default configuration file. Attach a BIOS console and issue the load command. The console will display log messages as the load sequence progresses, allowing you to check for the following: Network addresses Name resolution Service advertisement and response Bootp reply Download image path and file name Ethernet frametype Configuration file path and file name. The degree of progress made in these steps may also indicate where the problem is. Refer to "BIOS Console Operation" and "Logging During Load" for more details. Call the next level of support.

Replacing a 7318

This procedure will preserve the TTYx and LPx devices configured for this 7318. If this is a Model S20 with P10-style ports, perform the sequence below on each host on which this 7318 is configured.
1. Log in as root.
2. Run the SMIT command. To go directly to step 1f, enter the smit fast path: ts7318_mnu.
3. Select Devices.
4. Select Communication.
5. Select Serial Communication Network Server (ComNetServer).
6. Select ComNetServer Configuration.
7. Select Show/Change Configured ComNetServers.
8. Select the ComNetServer that was replaced.
9. Modify the ComNetServer Ethernet Address field to reflect the Ethernet address of the new ComNetServer.
10. Select Do.
Modify the bootptab file (etc/bootptab), if necessary, to reflect the new Ethernet address if the 7318 was replaced with a Model S20. This is done from the host where the 7318 boots.
Rename the customized configuration to reflect the new Ethernet address if there is a customized configuration file for this 7318. This is done from the host where the 7318 boots.
Update the NVRAM on the new 7318 to match the values on the old unit if the 7318 has customized NVRAM fields. Set these fields using the BIOS console.

Problems with Terminals

Terminal Problems
Symptom	Action
The terminal does not respond.	Verify the cabling.Verify that the terminal is enabled.Verify the transmission parameters.Run the procedure in "System Checkout Using the Service Aid" (Model P10 ports only).
You see garbled characters.	Verify the transmission parameters. Verify the slew rate. Verify flow control.
You see output to the terminal but the keyboard does not function.	Verify the transmission parameters.Verify the cabling.Run the procedure in "System Checkout Using the Service Aid" (operational for Model P10-style ports only).
You see missing or bad cursor addressing.	Verify the terminal type. Verify flow control.
Multiple sessions does not refresh the screen properly on switch.	Verify the terminal type.

Cabling

If you are using a modem control device, type the following from any host on which the 7318 software is installed to check the status modem signals:
```
cnsview -c "show modem" DeviceName
```
where the Devicename parameter specifies the name of the device, such as /dev/tty1. Data Carrier Detect (DCD) and Clear to Send (CTS) should both be 1.
If your cabling implements all of the RS-232 signals supported by the 7318 and has RS-232 standard DB-25 pinout, use the procedure for "System Checkout Using the Standalone BIOS Console" , "Run the Serial Port Wrap" and the serial port wrap plug supplied with the RS /6000 ( part number 6298964) to verify the complete cable path to the serial device.
For Model P10 ports, the 7318 Service Aid Advanced Test may be used rather than the BIOS Console procedure.
Finally, you can use an RS-232 tester plugged into the back of the terminal. The Transmit Data (TD) and Receive Data (RD) lines should be not asserted, and all other lines should be asserted.

Problems with Printers

Printer Problems
Symptom	Action
Serial printer not working.	Verify printer status. Verify printer enabled and accepting requests. Verify serial cabling. Verify printer model. Verify slew rate.
Parallel printer not working.	Verify printer status. Verify printer enabled and accepting requests. Verify parallel cabling. Verify printer model.
Terminal transparent printer not working.	Verify printer status. Verify printer enabled and accepting requests. Verify serial connection. Verify printer model. Verify that you are only sending ASCII data to the printer.
Garbage characters on serial printer.	Verify serial connection. Verify printer model. Verify slew rate.
Garbage characters on parallel printer.	Verify printer model.
Garbage characters on terminal transparent printer.	Verify terminal to printer connection. Verify printer model.
Characters dropped on serial printer.	Verify flow control.
Characters dropped on terminal transparent printer.	Verify transparent printer rate.
Attached terminal of terminal transparent printer stops responding.	Verify transparent printer rate.

Note: The procedure described in "System Checkout Using the Service Aid (for Model P10 ports or Model S20 ports configured as P10-style ports)" applies to all of the symptoms in the Printer Problems table.

Printer Status

Check your printer to make sure it is online, does not show an error condition, or is not out of paper.

Printer Enabled and Accepting Requests

Run the smit command.
Select Spooler (Print Jobs) from the System Management menu.
Select Show the Status of Print Jobs.
From the dialog, select yes in the Show the status of ALL print jobs? field.
Verify that the Status field for each printer indicates READY or RUNNING. Other values may indicate the printer is not working for various reasons (for example, out of paper, cable not attached, out of toner).

Serial Cabling

Use the cnsview command to check the status modem signals by entering the following:
```
cnsview -c "show modem" DeviceName
```
where the DeviceName parameter is the name of the device, such as /dev/tty01. CTS and DCD should both be 1.
If your cabling implements all of the RS-232 signals supported by the 7318 and has RS-232 standard DB-25 pinout, use the procedure for "System Checkout Using the Standalone BIOS Console" , "Run the Serial Port Wrap" and the serial port wrap plug supplied with the RS /6000 (part number 6298964) to verify the complete cable path to the serial device.
For Model P10 ports, the 7318 Service Aid Advanced Test may be used rather than the BIOS Console procedure.
Use an RS-232 tester plugged into the back of the modem. The modem control line should be asserted, the Data Terminal Ready (DTR) line may flicker, and the TD and RD lines should flicker as data crosses the tester.

Printer Model

Use the smit chgprt fast path to take you to the Change / Show Characteristics of a Printer/Plotter menu. Verify that the printer model matches the type of printer you have.

Parallel Cabling

Use the cnsview command to check the printer control signals by entering the following:

cnsview -c "show lptctl" DeviceName

where the DeviceName parameter specifies the name of the device, such as /dev/lp2.

When the printer is online but not printing, you should see:

`selected:`	1
`peb:`	0
`error:`	0
`selection:`	1
`init:`	0
`feed:`	0

If you do not see these signals, try replacing the printer cable.

Flow Control on a Serial Port

Use the smit chgprt fast path to take you to the Change / Show Characteristics of a Printer/Plotter menu. If your terminal is set for XON/XOFF flow control, the XON-XOFF handshaking field should be set to yes.

If your terminal is set for DTR flow control, ensure that the Use DTR communication protocol field is set to yes.

Slew Rate

To verify the slew rate on a Model P10 or on a P10 style port on a Model S20, perform the following:

Run the smit ts7318_mnu fast path.
Select ComNetServer Port Options.
Select Show / Change Slew Rates.
Select the ComNetServer containing the port group or groups to be displayed or changed.

To verify the slew rate on a Model P10 using the cnsview command, type:
```
cnsview -c "show slew" /dev/ttyN
```
To change the slew rate on a Model P10 using the cnsview command, type:
```
cnsview -c "set slew" Rate
```

To verify the slew rate on a Model S20, view the /usr/lib/cns/s20.cfg. Find the [PortNN] subsection that corresponds to the appropriate port. Find the stty entry and scan the line to find the slew setting. Refer to "[PortNN] Section" for details on the [PortNN] section and the stty=entry.

Transparent Printer Rate

Use the smit ts7318_prt_mnu fast path to view the transparent printer parameters in the Show / Change Configured ComNetServer Printers dialog.

Problems with Modems

Modem Problems
Symptom	Action
Modem does not answer.	Verify the cabling. Verify that modem auto-answer is enabled.
Modem will not dial out.	Verify the data rate. Verify the cabling. Verify the flow control. Verify the slew rate.
Modem answers with garbled data.	Verify the data rate. Verify the flow control. Verify the slew rate.

Note: The System Checkout Using the RS/6000 Service Aid (Model P10 ports only) applies to all of the symptoms in the Printer Problems table.

Cabling

Use the cnsview command to check the status modem signals by entering the following:
```
cnsview -c "show modem" DeviceName
```
where the DeviceName parameter specifies the name of the device, such as /dev/tty01. CTS should be 1. DCD should be 0 until the modem answers and should be 1 after it answers.
If your cabling implements all of the RS-232 signals supported by the 7318 and has RS-232 standard DB-25 pinout, use the procedure for "System Checkout Using the Standalone BIOS Console" , "Run the Serial Port Wrap" and the serial port wrap plug supplied with the RS /6000 (part number 6298964) to verify the complete cable path to the serial device.
For Model P10 ports, the 7318 Service Aid Advanced Test may be used rather than the BIOS Console procedure.
Use an RS-232 tester plugged into the back of the modem. The modem control lines should be asserted, the DCD line should not be asserted when there is no carrier, and the TD and RD lights should flicker as data crosses the tester.

Modem Auto-Answer is Enabled

Verify that the S0 register is not set to zero (disable auto-answer).

Data Rate

If you have configured your modem to use a fixed data rate (recommended), verify that the SMIT setting matches the modem data rate (usually 9600).

Flow Control

To verify flow control settings, perform the following steps:

Run the smit chgtty fast path.
Select a TTY from the list that displays.
Select Change / Show TTY Program.
Select the STTY attributes for LOGIN field and scan to the end of the field attributes. You should see ixon and ixoff indicating that the TTY is configured for XON-XOFF handshaking.
Select Change/Show Hardware Characteristics of a TTY.
1. If you set your modem for XON/XOFF flow control, the SMIT dialog should display yes for XON-XOFF handshaking.
2. If you set your modem for RTS/CTS flow control, you should confirm that the port is configured for RTS/CTS flow control.

To verify the flow control on a Model S20 port that is not configured as a P10-style port, view the default or customized configuration file for the 7318. Find the [PortNN] subsection that corresponds to the appropriate port. Find the stty entry and scan the line to find the flow control settings (ixon, ixoff).

Slew Rate

To verify the slew rate on a Model P10 using SMIT:

Run the smit ts7318_mnu fast path.
Select ComNetServer Port Options.
Select Show / Change Slew Rates.
Select the ComNetServer containing the port group or groups to be displayed or changed.

To verify the slew rate on a Model P10 using the cnsview command, type:
```
cnsview -c 'show slew' /dev/ttyN
```
To change the slew rate on a Model P10 using the cnsview command, type:
```
cnsview -c 'set slew' Rate
```

To verify the slew rate on a Model S20, view the /usr/lib/cns/s20.cfg. Find the [PortNN] subsection that corresponds to the appropriate port. Find the stty= entry and scan the line to find the slew setting. Refer to "[PortNN] Section" for details on the [PortNN] section and the stty=entry.