COMPARE the SENTRY Call Blocker V1 with CT-CID803

Below is a comparison table outlining the key features that differentiate the SENTRY call blocker and the T-Lock Call blocker products.  For a full list of features, please refer to the Info product details links:


Call Blocker Model CT-CID803

SENTRY Call Blocker1 blocker


CT-CID 803

CT-CID 808

Blocking Capacity2

Up to 1,500 numbers

Up to 1,500 numbers, shared3

Block Area Code(s)



Block Outgoing Calls



Can you add numbers you want to block manually?



Callers must listen to voice warning message



Product support

Email, Live chat, Phone

Email only

Initial Setup Required



Handset required for programming



Product Size5

4″ wide x
3.25″ length x 1.75″ height

5.50″ wide x
5.50″ length x 2.00″ height4


(1) Tel-Sentry claims to be able to eliminate 99.9% of live solicitor calls by playing a standard (non-changeable) voice warning message that says “If you are a telemarketer or a solicitor of any purpose please hang up and remove our phone number from your list, otherwise please press 0”.  However, in the real world 99.9% of the actual solicitors and telemarketers simply ignore this message and press 0 to reach a real person, especially politicians, charities, and scam artists.

(2) According to factory in China that manufactured both of these devices (please pay attention to the model and the HS code printed on both devices), the SENTRY has the same storage capacity as the T-Lock/Pro Call blocker.  However, there is some conflicting data according to the information printed in the packaging box, it says “1000 Black / White List” capacity.  Also, you will find some conflicting / incorrect information posted  in Amazon & eBay  by Tel-Sentry about this feature.

(3) One important detail to be aware of is that the 1,500 storage capacity available in the SENTRY device is shared among 2 lists: the Whitelist and the Blacklist.  Therefore depending on the number of phones you need to store in the Whitelist, it will reduce the capacity to store numbers in the Blacklist.  While the T-Lock/Pro Call blocker device has the entire 1,500 storage capability available to store Blacklist numbers.

Why is it important to have a call blocker device with a large storage capacity?
Phone scams & frauds have grown exponentially in the US and abroad in recent years.  US residential consumers are getting bombarded by several forms of scams and frauds (learn more about scams).  As per our current list of scam related phone numbers, there are over 600+ numbers.  These are just a few of the numbers being reported by victims of scams within the last 12-18 months!

(4) Tel-Sentry claims that there is no setup require yet according to the information printed in the user guide, customers must choose a language by pressing a button to rotate through options.  Without doing this this device will not work!

(5) Photos of products side-by-side:
compare sentry call blocker

What are the similarities among these 2 Call Blocker products?

·         Both can block incoming nuisance calls.

·         Both are line powered (e.g. require no external power supply or batteries)

·         Both have non-volatile memory to retain blocked numbers even if unplugged form power line.

·         Both can block phone numbers from 7 up to 16 digits in length, and area codes.

·         Both support Caller ID number display, and no name display.

·         Both can block calls with missing or modified caller id information including Private, Out of Area, Unknown, etc.

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