Saturday, September 3, 2022

No Audio when using Plantronics (Poly) headset

My headset, Plantronics (Poly) Savi 8220 Office Wireless DECT Headset worked well for more than a year. Then, out of the blue, the audio stopped working. During a conference call on Zoom, I couldn’t hear my colleague’s voice. But they could hear my voice. It worked again if I power cycled the headset base.


  • No audio is heard from the headset while you are on Zoom or Teams call.
  • I cannot hear the user, but the person on the other line can hear my voice.


Update the headset firmware.

Step 1

Download the Plantronics Hub Software at Downloads & Apps site.

Step 2

Once downloaded, make sure that your USB headset is plugged into a USB port on your computer directly. You will get a warning message as below.

Step 3

Look for “Notifications” that should appear in the upper right side of the screen. Click on that.

Step 4

On the next screen, you’ll be looking for “update”. Click on the ‘Savi 8200 Series.‘ If you click ‘W8220T’, you will get ‘USB Connection Required’ warning even though you connected the USB cable directly.

Step 5

On the next screen, you should see “Updating Firmware…”. And both notifications will be disappeared after upgrading only Savi 8200 Series.

In most cases, going through this firmware upgrade will fix many issues.



Saturday, August 6, 2022

My console cable didn’t work

I don’t know when my console cable (Cable Matters USB C to RJ45 Console Cable) didn’t work. It is unclear whether it was after changing the MacBook to the M1 or updating the macOS. I haven’t used a console cable in a while.

I re-downloaded and installed the driver from the Cables Matters support site, but it didn’t work. However, it works well when I use the USB-C type TRENDnet TU-S9 console cable, which was used in the old MacBook, along with a USB C to USB A adapter.

I talked to the manager about buying a console cable that supports USB-C, and he mentioned a software called Serial.

Here is a solution!

The Serial offered a 7-day free trial, so I tried it right away.
When I connect the Cable Matters Console Cable, it connects immediately without driver installation!

The price is not low at $39.99, but it is good because you can connect the console cable comfortably without installing a driver. It is recommended for network engineers who have struggled with connecting the console.

Serial 2

Supported Features

  • Hex View
  • SSH Support
  • Telnet and Raw Socket Support
  • Flawless Emulation
  • No Drivers

Additional Features

  • Compatibility
  • File Transfers
  • Profiles
  • Logging
  • Timestamping
  • Extended Baud Rates
  • Break Support
  • Bluetooth



Sunday, July 17, 2022

Extreme Switch - How to verify SSH algorithms in EXOS?

There are two ways to identify SSH ciphers used in EXOS.

Option 1. Using Nmap without ssh into the switch

Use the following command with Nmap in Linux, macOS, or Zenmap in Windows.
nmap -sV -p 22 --script ssh2-enum-algos

macOS:/Users/analysisman% nmap -sV -p 22 --script ssh2-enum-algos
Starting Nmap 7.80 ( ) at 2020-11-04 23:16 PST
Nmap scan report for
Host is up (0.0028s latency).

22/tcp open  ssh     OpenSSH 8.1 (protocol 2.0)
| ssh2-enum-algos:
|   kex_algorithms: (4)
|       diffie-hellman-group14-sha1
|       diffie-hellman-group14-sha256
|       diffie-hellman-group16-sha512
|       diffie-hellman-group18-sha512
|   server_host_key_algorithms: (1)
|       ssh-rsa
|   encryption_algorithms: (4)
|       [email protected]
|       aes128-ctr
|       aes192-ctr
|       aes256-ctr
|   mac_algorithms: (6)
|       [email protected]
|       [email protected]
|       [email protected]
|       hmac-sha2-256
|       hmac-sha2-512
|       hmac-sha1
|   compression_algorithms: (2)
|       none
|_      [email protected]
MAC Address: 00:04:96:9B:55:AD (Extreme Networks)
Warning: OSScan results may be unreliable because we could not find at least 1 open and 1 closed port
Aggressive OS guesses: Linux 3.2 - 4.9 (96%), Linux 3.11 (96%), Linux 3.1 (95%), Linux 3.2 (95%), AXIS 210A or 211 
Network Camera (Linux 2.6.17) (94%), Linux 3.10 (94%), Linux 2.6.18 (93%), Linux 3.16 (93%), Linux 3.18 (93%), Linux 2.6.32 (93%)
No exact OS matches for host (test conditions non-ideal).
Network Distance: 1 hop

OS and Service detection performed. Please report any incorrect results at .
Nmap done: 1 IP address (1 host up) scanned in 7.11 seconds

Option 2. CLI command in EXOS

The “show ssh2” command will show key type, ciphers, public key algorithms, etc.
show ssh2

X440G2-12p-10G4.2 # sho ssh2
SSH module configuration details:
SSH Access            : Enabled
Key validity          : Valid
Key type              : RSA 2048
TCP port              : 22
VR                    : all
Access profile        : not set
Secure Mode           : Off
Diffie-Hellman Groups : 14 (2048 bits), 16 (4096 bits), 18 (8192 bits)
Max Auth Tries        : 3
Idle time             : 60 minutes
Rekey Interval        : 4096 MB and no time limit
Ciphers               : [email protected], aes128-ctr, aes192-ctr, aes256-ctr
Macs                  : [email protected], [email protected], 
[email protected], hmac-sha2-256, hmac-sha2-512, hmac-sha1
Public key algorithms : ssh-rsa, x509v3-sign-rsa, x509v3-sign-dss
Login grace timeout   : 120 seconds

To enable or disable Cipher, use the following command.

# configure ssh2 enable cipher {all/<cipher>}

NOTE: You must have version or later (the previous version will not allow this command).


Extreme Switch - How to enable SSH in EXOS