• Here are some method of Call wait/hold/forwarding Activate & Deactivate ideas of NTC.
• 
  
• What is Call Wait feature?
  Call waiting feature informs customer about incoming call even if the customer is busy talking with another customer.
• How to activate/deactivate Call Wait feature.
  Option to activate deactivate call wait feature is normally present inside "Call Setting" menu of the phone. Or you can activate dialing *43# .Deactivate Using #43#. Check Call waiting status using code *#43#.
• Need to pay for Call Wait?
  No need to pay. It is free for Nepal Telecom subscriber.
• What is Call Hold feature?
  Call hold feature allows customer to place an active call on hold and initiate another call or answer an incoming call.
• How to Activate/De-activateCall hold feature?
  Nepal Telecom have already provisioned this feature for all its valued customer.
• Need to pay for Call hold?
  No need to pay. It is free for all Nepal Telecom subscriber.
• What is Call forwarding?
  Call forwarding allows you to forward your incoming calls to another phone number.
• Types of Call Forwarding?
  
  a. Unconditional Call Forwarding ( dial **21*Number# to activate )
  Forwards all of your incoming call to another phone number.
  
  b. Call Forwarding when busy (Dial **67* Number# to activate)
  Forwards an incoming call when you are busy with another call.
  
  c. Call forwarding when no reply (**61*Number# to activate)
  Forwards the call when you did not answer an incoming call.
  
  d. Call forwarding when not reachable (**62*Number# to activate)
  Forwards the call when your phone is out of network coverage or phone is switched off.
• How to Activate/De-activate Call Forwarding?
  Option to activate/deactivate above mentioned types of call forwarding is normally present inside "Call Setting" menu of the phone.or
  a. Unconditional Call Forwarding ( dial **21*Number# to activate,##21# to deactivate)
  b. Call Forwarding when busy(Dial **67* Number# to activate,##67 # to deactivate)
  c. Call forwarding when no reply( dial **61*Number# to activate,##61 # to deactivate)
  d. Call forwarding when not reachable( dial **62*Number# to activate, ##62# to deactivate)
• Need to pay for Call forwarding feature?
  If "A-number" is making call to "B-number" and "B-number" forwards call to "C-number" then "A-number" pays as if it is calling "B-number" and "B-number" needs to pay as if it is calling "C-number".
• Any limitation to Call forwarding feature?
  Calls can only be forwared to NT Network (PSTN/GSM/CDMA).
  Call forwarding when busy and call Wait feature cannot be simultaneously active.
  If you have NTPro , then you already have set call forwarding when not reachable to NTpro platform, if you again set unreachable forwarding to another number, your NTpro incoming will not work.

source: NTC