Standards for network design / installation diagramming in CAD

My question is very simple, is there a universally recognized standard for NEWTORK design CAD symbols which will cover all possible or frequent components ( firewall, switch, router, wifi antenna, DB, Backup disk, fiber/Ethernet cables, Rj45 socket etc etc .. ) and can be used in a plan for example ?

Your question is not as simply as it may appear. There are some widely accepted symbols in some cases, but in others there simply is not. So no, there is no universally accepted standard.

You compare this to symbols for electrical components as if these are fully globally recognized and accepted, but that is not the case 100% of the time. While most of that is fairly settled, there can be differences even between standards for different regions, especially when the needs of the location aren't entirely "typical" in some way. The producers of such drawings/prints/plans are free to use whatever they wish to convey their meaning, and sometimes that does not follow any sort of standard (of which there are several) or industry expectation.

Your best bet is to always reference the legend provided with the drawings to ensure your understanding of what is being presented. Or if you are producing such drawings, make sure to include one.

For example, often phone locations are represented by a black triangle, data by a white (with black border) triangle and phone/data locations by a triangle that is half back and half white. A little "W" next to it may mean a wall mounted location different than the "standard" height for such installations (also usually spelled out somewhere in the prints) or a "F" may indicate a floor installation. But what does a "data location" even mean in the context of that drawing (one data cable, two, three, six)?

What symbol do you use with odd locations such as one that is half power and half data (yes, this is against code in many locations, but I have seen it still done occasionally)?

Routers, switches and firewalls may be presented in a more "abstract" depiction, or the drawings may include full rack diagrams using images of the hardware that is actually to be installed in the rack (often provided by the vendors).

And all this varies from one architectural firm to another or one region of the world to another. Additionally, many architects will change the symbols they use at the customer's request if the symbols the customer is used to are different.

Until today I Just use my own symbols that I invented but understandably many times i find myself in need to explain to colleagues / installers what those really are and this is not a long term good solution.

As it seems you are producing such drawings, talk to your colleagues and some large contractors in your area. See what they use and are used to seeing. Modify your symbols to match theirs, build out the "standard" legend to include with your drawings, and use that unless someone requests you to use something different (and then do so with that entity/organization).

If your legend is sufficient, then you should not need to spend a lot of time explaining your drawings/prints to others. They will simply be able to check your legend to validate the meaning.

Is there a universally recognized standard for NETWORK design CAD symbols which will cover all possible or frequent components ( firewall, switch, router, wifi antenna, DB, Backup disk, fiber/Ethernet cables, Rj45 socket etc etc .. ) and can be used in a plan for example ?

In a word, No.

1. Network engineering is not a formal discipline like electrical engineering, and it is relatively new.
2. The technologies, devices, and features we use are constantly changing. In contrast, electrical components have been unchanged for decades.
3. Technologies, devices, and features are often developed by specific equipment manufacturers, who describe them and name them as they see fit.
4. The common terms we use: router, switch, firewall -- have no official definition by any standards body. For the most part, there is general acceptance of the functionality, but companies can (and often do) put all sorts of functions into a box and call it a router or firewall.