The Never-Ending Token Story

Energy meters with prepayment function are mainly working with the Standard Transfer Specification (STS). There are still some manufacturer specific proprietary solutions in the market.
Not only for security reasons, these solutions are not recommended.

Now there are more than 60 million STS payment meters installed worldwide. The IEC 62055-41 is the master document for STS operations. It's the most advanced and secure system for prepayment.

The Token

Tokens are used to transfer information in a secure way. In STS terminology, a token is a 20-digit number. To illustrate how a token looks like, click the button below.

function makefake(){ document.getElementById("h1″).style.display="none"; t1 = "Thanks for using our token generator."; t2 = "Please find your personal token below:"; max = Math.pow(10, 10);var min = max/10; var n1 = Math.floor( Math.random() * (max – min + 1) ) + min;var n2 = Math.floor( Math.random() * (max – min + 1) ) + min; a = ("" + n1+n2); a = a.replace(/(\d{4})/g, '$1 ').replace(/(^\s+|\s+$)/,"); t3 = a; t4 = "The token was generated at"; t5 = (new Date()); t6 = "This token will not work!" document.getElementById("token").innerText = t1 + "\r" + t2 + "\r" + "\r" + t3 + "\r" + "\r" + t4 + "\r" + t5+ "\r"+t6; }

The STS association has defined token for various tasks. The end-user needs mainly credit-tokens to top-up his credit.

The Meter Manufacturer can not provide tokens

To make this better understandable, let's take a look at a little graphic.

Sts Token Generation Principle
STS Token Generation Principle

You get your token from the power company service, or vending station. The energy meter must be registered in their vending system upon first installation. The reason behind is clear: You can't buy a token from power company A and use it for a meter supplied by power company B.
In addition, each power company has their own supply group code (SGC) with the matching encryption key. If the meter is registered, the security module generates a valid token (blue arrows). Then, you as user, get the token and punch it in at your meter key pad.

Tokens are for one time use only and have an expiry date. So you can't buy credit for the next twenty years.

Advanced Token Operations

Up to now, many utilities are operating according to the graphic. It's not very convenient for the user to go to the point of sales (POS) to join the queue for buying new credit.
With an AMI (Advanced Meter Infrastructure) solution together with bi-directional meter communication, it's possible to buy credit online.
Sooner or later, all power companies will follow this trend. Still, the security is maintained with the encryption at the security module. The AMI-system transfers only the token, so there is no need to enter it manually.


This article is pretty much simplified to make the end-user understanding, why meter manufacturers are not able to generate tokens.
The STS association is active in energy meter prepayment since 1993 and their concept hasn't been compromised until now.

Thank you for reading, and don't ask again for a token.

Editor's note: This article was originally published in August 2021 and has been updated for comprehensiveness.

20 Replies to “The Never-Ending Token Story”
    1. Some utilities are offering online vending, but it is doubtful that they would provide "clear tamper" tokens online. Tampering is a serious matter that can have significant consequences. If tampering is detected, it would require further investigation by the utility.

  1. Lauren company doesnt know anything about meters or tamper codes that's why he cannot provide them. Its sc@m

    1. Thank you for the unqualified comment. Try to understand the article. Meter manufacturers can't provide 'clear tamper' tokens. The meters are secured with a key. Only your power company has the key for your meter.

    1. Some utilities are offering an online service for credit tokens. I have never seen such service for a 'clear tamper code'. Tampering of a meter is a serious issue. This involves an investigation and can lead to penalty. So, I think it's impossible that you can apply for these tokens online.

  2. I have a itron ace9000 ciu which do not display anything,I mean blank screen and the power to it is ok.i learnt that all this model of meter are shutting what is the solutions.

    1. Thank you for your comment. Itron is another energy meter manufacturer. We can't deliver solutions for their products. Maybe by chance, one of our readers knows a solution.

  3. I like to know code which can unlock meter which have ordered temper in order to avoid the distabance with company

    1. Please take your time to read and understand the article.
      There is no such code.
      Only Your power-company can make one, for single use on a single meter.

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