Yorkshire-based Pace Micro could suffer from an NTL decision to switch its supplier of digital set-top boxes to Samsung.
Pace has supplied more than 2.25 million set-top boxes to NTL, but the cable company said that Samsung's SMT-2100C product had more interactive features and was cheaper.
Pace seems to have been caught as NTL battles to slash more than £12m worth of debts: Samsung's set-top box is 30 per cent cheaper than Pace's model.
NTL's contract with Samsung is worth more than £30m.
However, an NTL spokesman said the company would continue to use Pace and Samsung was a "second supplier".
"Having a second set-top box supplier is good for our business and we are delighted to welcome them on board. It will deliver NTL with significant cost benefits and enhanced product reliability."
But things are not going well for Pace, whose shares plunged 67 per cent last week when it warned that full-year turnover would be a third lower than expected.
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