Networked telecoms group BATM Advanced Communications warned it expects first half revenue and profit to be materially below management expectations.The group, which provides technologies for the networked telecoms and medical laboratory equipment markets, said components supplied by third parties failed to arrive during May as scheduled, and consequently it was unable to fulfil orders and was forced to postpone deliveries."However, the backlog remains substantial and, with certain components required to complete some orders having been received, the group is working towards clearing this in the second half of 2013," it explained.It added: "Separately, due to ongoing global economic and commercial uncertainty, the group has re-enforced its policy of tight credit control for certain customers of the distribution business of the Medical division whereby shipping should only occur once payment has been received by BATM or it has complete confidence that payment will be forthcoming."As a result, BATM was forced to stop supplies to certain major customers globally during May 2013, which resulted in revenues in this business being lower than anticipated. While first half revenue and profit is expected to be materially below management's expectations, on a more encouraging note, it said trading in June has started very well and its businesses are returning to normal. BATM expects its second half performance to be in line with management's expectations and for the full year to December 31st 2013 as a whole, it still expects to achieve higher revenue and profit than the previous year."Looking ahead, the fundamentals of the business remain strong," it said.Its shares slumped 22.50% to 15.50p at 08:30 in London.