Channel 4 has admitted that its access services may not be fully up and running until the middle of November.
On September 25, a false fire alarm at playout firm Red Bee Media led to most of Channel 4's TV stations coming off air for a period - in addition to causing problems with All 4 and access services including subtitles, audio description and sign language.
In a lengthy statement, the broadcaster explained that it activated its emergency backup system, which brought most of its TV channels back to air, but the backup for access services failed and now a new system is having to be built from scratch.
"This is a complex job, as a large number of different systems at Channel 4 and beyond have to talk to each other to make this work," the statement said. "Until now, all testing has been overnight as we couldn't risk coming off-air again.
"However, we are beginning to make progress. For example, some of you might have noticed we have been testing subtitles on More4 and Channel 4 during the day."
It added: "We have been rebuilding the system over the last few weeks, and there is still a considerable amount of work to be done. We cannot rush this and run the risk of something going wrong.
"Something like this needs to be installed slowly to ensure our channels don't come off air and to prevent something like this happening again. That means that full access services might not be available until the middle of November. Clearly, if we can do anything to speed up this process, we will.
"We know that this will be incredibly disappointing to everyone, but we do need to get this right. In the meantime we will continue to put our most popular programmes that you have missed, with subtitles on All 4."
The broadcaster did not provide any update on its catch-up programming service on Sky, which has not been added to since the incident.