1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 3 TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%,%2!0(9!,0(!“%4)#!,G0G04%,%2!0(G0G04%2-).!,%15)0-%.453%G0G0/amended at New Delhi, 1960 and Geneva, 1980)The CCITT,considering(a) that when a station is equipped with receiving reperforating equipment, it is
2、 often necessary to clear theperforated tape of the perforator to ensure transmission of the last characters of a message received during theperforation of the first characters of the next message;(b) this operation of clearing the tape may lead to mutilation of the beginning of the message that is
3、beingperforated (particularly if insufficient message separation signals have been transmitted);unanimously declares the view:(1) It is recommended that arrangements be made to avoid the mutilation of signals transmitted at the head of amessage and received on start-stop reperforating equipment.(2)
4、If the reperforator is provided with local means for feeding the paper, not more than one multilated signalshould be tolerated. The wording of the message must make allowances for this fact.(3) It is recommended that message separation signals should be sent at the end of a batch of telegramsfollowi
5、ng a given route at centres equipped with receiving reperforators. The choice of the type and number of signalsto be sent for this purpose is left for agreement between the Administrations concerned. Use of a series of letter-shiftsappears particularly desirable for this purpose.(4) If the reperfora
6、tor is to be switched into circuit and out of circuit under control of the transmitting station,the following sequences of signals should be used:combination No. 3 repeated 4 times (CCCC) for switching the reperforator into circuit by remote control;combination No. 6 repeated 4 times (FFFF) for swit
7、ching the perforator out of circuit by remote control.(5) These operations may equally well be controlled by the secondaries of CCCC and FFFF but, forconvenience in operating the primary signals, CCCC or FFFF only should be used by operating staff.(6) If the FFFF sequence has not been received befor
8、e the arrival of the clearing signal (or the end-of-messagesignal), receipt of the clearing signal (or the end-of-message signal) should cause disconnection of the reperforator.However, reception of the FFFF sequence should have no effect if the reperforator was previously connected by theoperator at the receiving station. The CCCC and FFFF sequences should not affect the reperforator at the transmittingterminal.
