Chargeable Units(MB) Excluding Night Unlimited, It is the term used on Broadband/Data Connection Bill, that means if you have a Broadband connection for example BSNL Broadband connection they have GB wise broadband tariff but in some tariff you will get unlimited Night usage (2AM to 8AM) which is not included to the MB/GB according to the tariff. Look at the following example of BSNL broadband tariff which provides Night Unlimited Usage.
BSNL Broadband Plan For Night Unlimited Usage
BBG FN Combo 600 ( BSNL Broadband Plan with Night Unlimited)
|BBG FN Combo 600|
|Bandwidth (Download Speed)||Upto 2 Mbps|
|Monthly Charges (Rs)||600|
|Annual Payment Option (Rs) [11 x FMC]||6600|
|Two Year Payment Option (Rs) [21 XFMC]||12600|
|Three Year Payment Option (Rs) [ 30 X FMC]||18000|
|Download/Upload Limit (MB/ GB) per month||2.5 GB|
|Additional Usage Charges/MB beyond free download/upload limit (Rs)||Rs. 0.30/- per MB for usage upto 5 GB ; Rs. 0.15/- per MB thereafter|
|Night Unlimited (0200-0800 Hrs)||Yes|
So According to the above plan you have a monthly charges of Rs 600 with 2.5GB per month, to clear 2.5 GB will be used between 8AM to Night 2AM and the Night usage from 2AM to 8AM will not include in your bill amount it's free.
If the usage exceed the limit of 2.5 per month which is from (0800 - 0200Hrs, 8AM to 2AM) then the charges/MB will be Rs.0.30.
If you want to use this feature of BSNL broadband check your tariff details on the BSNL website to confirm that do you have the Night Unlimited Broadband Usage.