I want to set speed dial on my KX-TG4011 - Panasonic KXTG4011 Cordless Phone

Not normally, because would you want Julie in Accounting speed dialling your Husband by mistake. Making wide assumption you are female, but you get the drift. Manuals and video in the link.

https://www.google.com/search?q=setup+the+speed+dial+on+the+main+set+of+the+PABX+KX-TEM824+can+i+use+the+speed+dial+on+the+extensions

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There doesn't appear to be a way. Sometimes on multi-phone business systems, a technician can connect a laptop with dealer software and make changes or edits that a user can't.

If that particular number needs to be at Number 1, you would have to delete them all and reprogram them all again.

http://www.voicesonic.com/panasonic/manuals/KX-T76xx_User_Guides/KX-T7630_User_Guide.pdf

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Free manual but unsure about speed dial setting:

ftp://ftp.panasonic.com/telephone/om/kx-tg4011_mul_om.pdf

http://service.us.panasonic.com/OPERMANPDF/KXTG4011-MUL.PDF

See page 18 of this manual http://service.us.panasonic.com/OPERMANPDF/KXTG1032.pdf

Follow the instructions beginning on page 27 of the manual.

This model doesn't have a speed-dial or one-touch dialing feature. It does have a phonebook feature that allows you to store up to 50 phone numbers, and you can select an entry and the phone will dial automatically. Not quite the same, but it's all that's offered. The manual gives the steps for entering names and numbers into the phonebook, and for selecting and dialing an entry.

Hello, from the Switcboard / Main telephone ( usually ext 101, 10 or 9 ) with the handset on the cradle press Program * # followed by the system password ( default is 1234). Now press 001 and then SP-PHONE. Enter the system speeddial location ( 00 to 99 ) or just press SP-PHONE again to go to 00. Now enter your line access number ( usually 0 or 9 ) followed by the telephone number you would like to assign for the speeddial. Now press AUTO DIAL / STORE to save your setting. To go to the next speeddial location press SP-PHONE and follow the above steps again. Press Program to exit program mode. To dial the system speeddial from any extesion lift the handset and press * followed by the speeddial location ( example 00 )
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So I guess that means you're not programming SYSTEM speed dial numbers. Those are programmed from the system manager or operator's station. Personal speed dials are 1-0 and are programmed per set.

Carl