In telecommunication, a synchronous network is a network in which clocks are controlled to run[?], ideally, at identical rates, or at the same mean rate with a fixed relative phase displacement, within a specified limited range.

Note: Ideally, the clocks are synchronous, but they may be mesochronous[?] in practice. By common usage, such mesochronous networks are frequently described as "synchronous."

Source: from Federal Standard 1037C and from MIL-STD-188