BT said its first countrywide walkout for 13 years had had a "minimal" impact, though callers experienced delays.
But the Communication Workers' Union, which represents BT call centre staff, said the company had already proposed new talks for later this week.
Up to 4,000 BT staff at about 40 call centres - which deal with queries about sales, bills and repairs - are estimated to have taken part in the 24-hour stoppage, which follows an 81% yes vote on a 50% turnout.
But the company has been able to rely on a minority of non-union and agency workers - who could not be balloted because of laws against "secondary action" - to fill part of the gap.
A second one-day strike has been called for December 10.
Jeannie Drake, CWU deputy general secretary, said the strike had been solidly supported and represented "years of mounting frustration" at BT call centres. One of the flashpoints had been threats of displinary action if calls were not completed within 285 seconds.
But discontent is also focused on what the union describes as a management culture of harassment and bullying, increased use of short-term contract agency workers and inadequate staffing.
BT says it recognises there are staffing problems and has stepped up recruitment to deal with the complaint. The company wants to maintain a dialogue with the CWU to resolve the dispute.
But one striker at a Glasgow call centre said: "The decision to take industrial action has not been taken lightly. Talks have been ongoing over the past year with BT, but the company would not move on any of the important issues".
Call centres are Britain's fastest-growing industry and now employ more than 400,000 people.
