Abstract: An information communication system having a plurality of terminal equipment units, a network termination unit, a receive (R) line, and transmit (T) line. The terminal equipment units are commonly connected to the R and T line so as to communicate with the network termination unit. The communication is achieved in the form of successive frame signals, each composed of at least successive channels. Each terminal equipment determines a delay time for channel insertion into the frame signal on the T line. the delay time is determined during a learning identification algorithm operation which takes the transmission delay time along the R and T lines into consideration.

Abstract: Compounds of formula (I): ##STR1## (in which: R.sup.1 and R.sup.2 are the same or different and each represents hydrogen or a hydroxy-protecting group:R.sup.3 represents an alkyl group having from 1 to 12 carbon atoms which is optionally substituted, an alkenyl group having from 2 to 12 carbon atoms, an alkynyl group having from 2 to 6 carbon atoms or a cycloalkyl group which is optionally substituted; andX represents an ethylene group, a trans-vinylene group or an ethynylene group) and salts and esters thereof are useful intermediates in the conversion of 5Z-carbacyclin derivatives to their 5E-isomers and in the preparation of certain other carbacyclin compounds.