Narrative:

During preflight at the gate; both the first officer and I were explaining to our two reserve international relief officer's the data link procedures for attaining a clearance at our departure airport. The proper procedures were used; the data link appeared to work fine and the clearance was requested. I then left the cockpit and upon return got our briefs completed; ran the required checklists and felt ready for pushback and start. We started and were heading over to 22R for a full runway departure. Approaching the hold short line; tower told us to check our transponder on and we were subsequently cleared [to] line up and wait. The first officer verified the transponder was on but on second glance; noted the code was 0000. I asked the international relief officer to grab the clearance printout and verify the squawk. He couldn't locate it so we simply asked the tower to verify our code. He quickly gave it to us and cleared us for takeoff. At 900 feet departure cleared us to 6;000 feet and we were on our way. I then checked for the paper clearance and when unable to locate it; I went to the computer. It was not there. Realizing that we may not have copied the clearance; I immediately checked with ATC/ departure to ensure they had our flight plan. They said yes; no problem and we continued on our way with no additional problems.

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Original NASA ASRS Text

Title: A B777 Captain instructed the IRO's about data link clearance procedures then left the cockpit only to discover during taxi that the Clearance PDC had not been obtained because no transponder code was available.

Narrative: During preflight at the gate; both the First Officer and I were explaining to our two Reserve IRO's the data link procedures for attaining a clearance at our departure airport. The proper procedures were used; the data link appeared to work fine and the clearance was requested. I then left the cockpit and upon return got our briefs completed; ran the required checklists and felt ready for pushback and start. We started and were heading over to 22R for a full runway departure. Approaching the hold short line; Tower told us to check our transponder ON and we were subsequently cleared [to] line up and wait. The First Officer verified the transponder WAS on but on second glance; noted the code was 0000. I asked the IRO to grab the clearance printout and verify the squawk. He couldn't locate it so we simply asked the Tower to verify our code. He quickly gave it to us and cleared us for takeoff. At 900 feet Departure cleared us to 6;000 feet and we were on our way. I then checked for the paper clearance and when unable to locate it; I went to the computer. It was not there. Realizing that we may not have copied the clearance; I immediately checked with ATC/ Departure to ensure they had our flight plan. They said yes; no problem and we continued on our way with no additional problems.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.