The Election Commission on Wednesday issued revised protocol for handling and storage of symbol loading unit  (SLU) of Voter Verifiable Paper Audit Trail (VVPAT) slips against the Electronic Voting Machine (EVM). This comes in the backdrop of the latest order by the Supreme Court which said, "After the completion of symbol loading process, the symbol loading unit (SLU) should be sealed in containers. The SLU should be stored at least for a period of 45 days." The SLU uploads the name and symbol of the candidates contesting on a particular seat on VVPAT or paper trail machines.

In a statement on Wednesday, the poll authority said all State Chief Electoral Officers have been directed to create necessary infrastructure and provisions to implement the new protocols for handling and storage of the symbol loading units (SLUs).

"As mandated by the Supreme Court, the revised protocols are applicable in all cases of completion of the symbol loading process in the VVPATs undertaken on or after May 1, 2024," the commission said.

Currently, only the three components of the EVM — the ballot unit, control unit, and VVPAT — are stored for 45 days after the results.

This is the first time that SLUs, used to load candidate symbols onto the VVPATs, will also be available for examination along with the EVMs if a candidate challenges the results by filing an election petition in court. The EVM and VVPAT slips can be called by the court while hearing the plea.

The SLU is used to load the symbols of the candidates onto the VVPAT.  It is a matchbox-sized device that is first connected to a laptop or personal computer, from which a symbol loading application is used to load a bitmap file containing the candidates' names, serial numbers, and symbols.

The SLU is then connected to the VVPAT to transfer that file on to the paper audit machine. This is done under the supervision of a district election officer.

As per the SOP, during the commissioning period in Assembly Constituency/Segment, all Symbol Loading Unit(s) along with its accessories shall be in the custody of the Returning Officer/Assistant Returning Officer, as the case may be and shall be securely stored in locker/safe/cupboard etc. under lock and key in the Commissioning premises with proper security. RO/ARO shall be responsible for safe custody of Symbol Loading Unit(s) along with its accessories during the commissioning period.

Each set of SLU along with its accessories used in a particular AC/AS shall be kept in a separate container. Not more than one set of SLU along with its accessories should be kept in a container.

"After sealing the SLU containers, the same shall be deposited with the District Election Officer concerned within 24 hours of the completion of commissioning. These containers shall be stored by the DEO in a separate strong room/secured room and shall be marked clearly on the door as 'SLU STORAGE ROOM'. It is clarified that both the used SLUs and Reserve SLUs shall be stored in the SLU Storage Room. District Election Officer shall be responsible for their storage and security. The SLU Storage Room shall be under double lock system with all keys of each lock with two separate specified officers," it said.

While rejecting the plea for 100 per cent verification of VVPAT slips against the Electronic Voting Machine (EVM) count, the Supreme Court on Friday (April 26) directed the EC to "seal and secure" the Symbol Loading Unit (SLU) for 45 days after the declaration of election results. This means that a candidate can ask ECI officials to check the one-time programmable software in the BU (Ballot Unit), CU (Control Unit), and VVPAT for tampering, in case of any doubts regarding the result. This verification involves inspecting the burnt memory/ microcontrollers of these three components.

Before the Supreme Court order, the SLUs were handed over to local poll officials by the engineers of BEL or ECIL. A day after the poll, the SLUs were returned to the engineers of the two public sector units who manufacture the ballot unit, the control unit and the VVPAT along with SLUs.

A few years ago, a feature was added which helped the candidates or their representatives see the symbol loading process on a TV monitor. The feature was added to enhance transparency.