How do I change the ringtone on Nortel/Meridian NT4X37 and NT4X42CA

your phone's LCD display is defective and it should be changed. I have a similar problem but till it works that way, I can live with it. Actually I have 3 more with good display - hehe....

If annoys you, get a used one from Amazon for 44 USD

http://www.amazon.com/Nortel-Meridian-M7208-Telephone-Gray/dp/B0018JVOP2

Sending it to repair might cost you more.

Press Feature * 3
press the 5th line key you want to use for paging
enter the page-all code (feature 601-603 as you wish)

When you connect a Nortel Meridian M3820 phone to a 3300 CITELlink Gateway andprogram it as a CITELlink Type2 device, ... Button Label. Function ... Feature Key 4. 11. Feature Key 5. 12. Feature Key 6. 13. Program. 14. Menu Right

Here's where you can get the manual:

http://www.telephonemagic.com/phone-support/meridian_1_m2000_phone_manuals.htm

http://www.best4systems.co.uk/_design/best4systems/_pdf/Phones/Meridian_Option/Meridian_Norstar_M3820_M3310_M3110.pdf

Above is your manual this should sort things out.

Not too sure what type of manual you are looking for, but here is a useful link to have for a Norstar system information.

http://www.alphatelecom.ca/meridian_norstar_manuals.htm

Feature *6

LD 32
CPWD L S C U

Feature *1, Press the desired key, dial the #