I have 3Com Baseline Switch 2924-SFP Plus i need to manage it but i forget the administrator password how can i reset this switch to manufacture configuration or how to reset the password

Connect the console cable, open a connection to the serial port via a utility such as PuTTY, and do the following:
1) Enter the user name "recover" and password "recover" to place your unit in password recovery mode. The unit will remain in password recovery mode for 30 seconds max.
2) Perform a hard reset by removing power, waiting 10 seconds, and then re-applying power.
3) Once the switch has rebooted, enter a new password for the "admin" user account.
4) Enter enable to leave password recovery enabled, or enter disable to turn it off. You are now logged in as the default "admin" user.
Note: If password recovery has been disabled, the only way to recover access is to return the switch to 3com.

To re-enable the Console access requires the SW2900 series to be reset to its default settings via the WEB INTERFACE
- Web Interface
- Device >Configuration >Initialize To change the Default User "ADMIN" password it is necessary to use the Console connection
-Console Interface
-Once the unit has successfully booted and the prompt presented
-Enter "password" (without "")
-Enter "admin" when the system prompts for User
-Press the "Enter" key when the system prompts for "Old Password" (the ADMIN password was reset by the Web Interface commands)
-Enter "" when the system prompts for the New Password (where "" is the new product ADMIN password)
-Enter "" when the system prompts to confirm the New Password In order to complete the configuration it is necessary to save the configuration via the WEB INTERFACE
-Web Interface
-Device > Configuration > Save
Symptom:
SW2900 Baseline Switch - Default console access disabled following password change
From the web interface, the default user "admin" password is changed and console access is disabled
Cause:
When applying the new password, by default the service-type is set to "telnet". When applied, the default "terminal" setting is removed thus disabling console access.

Don't let the switch name fool you, HP calls it the HP 1910.
HP 1910 48G Switch Fixed Port Web Managed Ethernet Switches HP JE009A ABA
Technical Notes:
"The HP 1910-48G Switch (JE009A) was formerly sold as the 3Com Baseline Plus 2952 (3CRBSG5293) and may ship with this product labeling.SFP ports and copper ports work simultaneously, independent of each other to give a total of 52 Gigabit-capable ports."

Firmware download from HP:
My Networking HP Official Site

https://community.hpe.com/t5/Comware-Based/Firmware-for-3com-Switches/td-p/7000310#.YPrrkI5KiUk

https://www.google.com/search?q=2948-SFP+Plus+firmware

..

1.what type of fiber is:SM (single mode) or MM (multi mode)?
2.what type of sfp? 1550 or 1310 if is SM, how many conectors and what type of conectors
3.in 3com usualy u dont need to make a port anouncemant as u need in cisco so if the sfp are ok, i mean if they are pairs and the fiber is same type should work, second problem : sometime the cisco sfp(when is not original from cisco) got problem in other brands hapend to me whit zyxel sw,

so give me more data and i will help you

thanks

If it's the Power Plus (3C16475BS) model, there should be a reset button inside a small hole on the back. "10 - Recovery Button" Inserting a paperclip or similar to reset. If it's not the Power Plus model and is in fact (3C16475A), this is an unmanaged switch, with no administrative capabilities. You don't need a password.
http://www.3com.com/products/en_US/detail.jsp?tab=features&pathtype=purchase&sku=3C16475BS

select restore factory default in administration tab or push reset button

Manual can be found at the following web site:
http://support.3com.com/infodeli/tools/switches/baseline/3Com_Baseline-Switch-2916-2924_User-Guide.pdf

The resetting of the password requires the installation of a console cable to the console port.

Be sure the terminal emulator program is set to VT-100 management using compatible, 38400 baud rate, no parity, 8 data bits and Console connection one stop bit.

Use the included cable, or be sure that the pin-out complies with a standard null-modem cable

Once the cable is connected, reboot the switch. Type a Ctrl/C until you enter the failsafe mode. This will be denoted with the prompt: “CFE>”
At the prompt execute the following commands:

CFE> passwrd
CFE> reset -sysreset

At this point the password has been reset.