Recommendation U.63
GENERAL REQUIREMENTS TO BE MET IN INTERFACING THE INTERNATIONAL
TELEX NETWORK WITH THE MARITIME “DIRECT PRINTING” SYSTEM
(Malaga–Torremolinos, 1984)
	The CCITT,
considering
	(a)	that it is desirable that the interface between the international telex service and the maritime “direct printing” system be defined;
	(b)	that the CCIR is charged with the task of making Recommendations relating to the radio path;
	(c)	that explanation of the details of the interface between the international telex network and the maritime “direct printing” system would be of assistance to the CCIR,
unanimously recommends
	that the following points should be taken into consideration when interfacing the maritime “direct printing” system to the telex network:
1	General
1.1	The maritime “direct printing” system should be capable of interfacing the international telex network in one or more ways:
–	in accordance with Recommendations U.1, U.11 and U.12 for direct real–time operation,
–	in accordance with Recommendation F.132 for ship originated access to maritime store–and–forward units,
–	in accordance with procedures defined in Series F and U Recommendations for store–and–forward access by terrestrial subscribers.
1.2	Answerback signals from the ship should be obtained both at the beginning and at the end of the call. When such signals are transmitted into the telex network, the coast station should make sure that they consist of 20 consecutive characters and are sent at cadence speed.
	The answerback should be in accordance with Recommendation F.130.
1.3	If the coast station detects an end of telex message signal from the ship, the existing terrestrial connection (if any) must be cleared down and a new connection established for the next telex message. This should apply also when the next message is intended for the same terrestrial subscriber.
1.4	For ship originated calls, the coast station should be capable of returning to the ship any service codes received from the telex network.
1.5	For land originated calls, service codes should be returned to the telex network in accordance with Recommendation F.131.
2	Special conditions related to ship originated calls
2.1	The selection signals received from the ship should have formats in accordance with Recommendation F.60, § 3.2.2.
2.2	When accessing a maritime store–and–forward unit, the call control procedures should be in accordance with the relevant Recommendations in the Series F and U.

2.3	For direct access into the telex network, the normal telex procedures given in Recommendations U.1, U.11 and U.12 should be followed. In particular, the requirements given in these Recommendations with regard to the sending of selection signals, end of selection signals and class of traffic signals should be observed:
–	Recommendation U.1, § 6,
–	Recommendation U.11, §§ 7 and 9,
–	Recommendation U.12, § 3.5.
3	Special conditions related to land originated calls
3.1	For direct access from the telex network, the time–out requirements of Recommendation U.1, U.11 and U.12 should be observed:
	Types A and B signalling (Recommendation U.1)
	The time from the end of selection, combination No. 26 (+), or last selection character received and the return of the call connected signal should not exceed 60 seconds.
	Type C signalling (Recommendation U.11)
	The time taken from the end of selection signal, combination No. 26 (+), to the call–connected signal should not exceed 60 seconds (see Table 1/U.11, remarks relating to the call–connected signal).
	Type D signalling (Recommendation U.12)
	The time taken from the end of selection signal, CSC code No. 11, to the call connected signal should not exceed 90 seconds (see Recommendation U.12, § 3.11).
	Note – It should be noted that for types A, B and C signalling, the same timings pertain to service signals (NP, NC, NA, OCC, etc.), and that in addition for type D signalling the same timing pertains to the last backward path signalling characters and terminating–through–connection.
3.2	If the time–out requirements cannot be met, the coast station may offer the calling subscriber, by an appropriate service code, a store–and–forward unit for forwarding the call to the ship.
4	Maritime group calls
	The provisions given in Recommendation U.62, § 4 apply.