Write to RFID 125kHz TAG

Hi,

I recently purchased RFID reading module RDM6300. Which works like a charm, but I am wondering, if I can write data with this modul?
Or is it even possible to write to 125kHz tags? Also how to check, if tag is not read-only?

Thanks for any guidance, how to write some data to my RFID tags.

EDIT:
Here: http://forum.arduino.cc/index.php?topic=116150.0 I discovered that most 125kHz tags, are read -only, because they have room only for manufactured ID, which is used for identification. But on ebay, there is a lot of rewritable 125kHz tags: rewritable rfid 125kHz

Or is it even possible to write to 125kHz tags?

Yes it is, but not with that reader.

Also how to check, if tag is not read-only?

Tricky, the only writable RFID card I have come across is slightly thicker and looks like two pieces of plastic being jointed together.

how to write some data to my RFID tags.

Why do you want to do this?
You do not write data on these cards you write the ID number that the card will send to the reader. There is no room for data.

Ok, I want to make copy of my entry-door tag. Ideally I would like to buy 125kHz sticker tag and rewrite this ID with original tag id.

Is there some cheap way how to do it?

Ok, I want to make copy of my entry-door tag.

If there is a legitimate reason for this then ask the people who administer the system and they can issue you with an other tag that also opens the door, if they consider it legitimate.

Sorry I don’t help people do illegal acts.

I've been working with RFID projects since about 2012, my first project involved java cards, cards with enough storage for little java applets. I've worked in 125khz range and the 13.56mhz. Most of the cooler applications are on 13.56mhz rfid technologies.

There is the t5577 a single layer (Not Clamshell Like Grumpy_Mike mentioned) rfid card that can be programmed as fsk, psk, manchester, hid II, and several other card formats and modulations. They're very neat cards. I work building RFID systems for business and I must say I do RFID stuff at home and my own doorlock is rfid enabled. So I disagree about this being an illegal act. If you're interested in doing this still check out the proxmark III you can get one for about $70 bucks. between having a proxmark III and the Proxmark forums you can do most anything with the T5577 I bought 100 of these cards for $40. I use them and a bluetooth low energy beacon to control lighting and music as I enter rooms of my house and unlock doors. Also never do anything with weigand or PSK modulation if you want it to be secure. The technologies are too open and well documented a 12 year old with a $15 reader/writer from china can break that tech.

Also never do anything with weigand

If you have worked professionally with RFID I am supprised that you mix up an interface standard with a technology. Weigand is just a way of transferring data to a controller just like RS232. It did start out as a technology but it hasn’t been arround now for about 40 years.