1、CEPT T/CS*49-02*E m 2326414 0004880 9 m TCS49-02 Page 1 E Recommendation T/CS 49-02 (Ostend 1979, revised in Vienna 1982 and Montpellier 1984) SYSTEM L1 DECADIC PULSING INTERREGISTER SIGNALLING Recommendation proposed by Working Group T/WG I 1 “Switching and Signalling” (CS) Revised text of the Reco
2、mmendation adopted by the “Telecommunications” Commission: “The European Conference of Postal and Telecommunications Administrations, considering that rotary dial telephones are still widely used on private automatic branch exchange extension lines; - that equipment located at subscribers premises a
3、nd used for private networks may be based on decadic pulsing techniques, recommends that the members, in conditions requiring decadic pulsing over links between analogue transmission interfaces of private automatic branch exchanges located in different countries, use System L 1 signalling as specifi
4、ed below.” 1. 1.1. 1.2. 1.2.1. 1.2.2. 1.2.3. 1.2.4. 1.2.5. 1.2.6. 1.3. GENERAL Line signalling System L1 decadic pulsing signalling is used in conjunction with System L1 line signalling according to Recommendation T/CS 49-01 i. The individual line signals to be provided and their uses are specified
5、in Recommendation T/CS 49-03 on the System L1 decadic pulsing call control signalling procedures 2. Principles and field of application The decadic pulsing interregister signalling system is to provide automatic and semi-automatic working between private automatic branch exchanges (PABXs) via terres
6、trial circuits. The system is a single voice frequency (1 VF) in-band signalling system, using the same signalling frequency of 2,280 Hz as System L1 line signalling, according to Recommendation T/CS 49-01 i. The use of voice frequency signals renders the system suitable for all voice transmission m
7、edia. The system is for use on four-wire circuits, and the PABX termination arrangements set-out in Recommen- dation T/CS 49-01 i apply. The decadic pulsing call control signalling operates on a link-by-link basis and may be used to set-up multi-link tandem connections. In accordance with CCITT Reco
8、mmendation 4.25 3, the signals are contained within the appropriate link and are not allowed to spill-over into subsequent links. The maximum number of tandem connections over which a call may be set-up is determined by the type of interconnecting circuits and is subject to mutual agreement by the p
9、arties concerned. All circuits used in System LI links should be to the standard of CCITT Recommendations G.171 4 and M.lO1O to M.1060 5. Forward signals may be passed while speech or audible indications are being received in the backward direction. Signals for decadic pulsing For System L 1 decadic
10、 pulsing signalling, the following signals in accordance with Recommendation T/CS 41-01 6 are specified. Forward signals - Address signal; - Proceed-to-send-on-recall signal. 1.3.1. CEPT T/CS*qq-OZ*E W 232b4l14 OOOLI883 O W Signal Address Digit 1 TICS 49-02 E Page 2 Code one tone-on pulse 1.3.2. Pro
11、ceed-to-send-on-recall (optional) Reconnect (optional) Backward signals - Proceed-to-send signal; - Address-complete signal; - Address-complete, extension-free signal; - Address-complete, extension-busy signal; - Busy-extension-changed-to-free signal; - Clear-request signal ; - Proceed-to-send-on-re
12、call signal. single tone-on pulse double tone-on-pulse 1.3.3. Clear-request when common-control equipment or switching equipment is released A clear-request signal shall be applied, prior to the answer signal when, after recognition of a seizing signal, no address or incomplete address information i
13、s received and the incoming PABX times-out, dismissing any common-control equipment. A clear request signal may be applied prior to the answer signal when an incoming PABX encounters congestion or an engaged extension and releases the switching equipment. 2. DECADIC PULSING SENDING AND DETECTING REQ
14、UIREMENTS 2.1. Signal codes Address signals (routing digits and extension number) are sent as pulses of signalling tone character-by- character in a non-compelled mode of operation in the sequence required by the numbering arrangements. The interregister signals shall be coded as shown in Table 1 (T
15、/CS 49-02). two three four five six seven eight nine ten tone-on pulses tone-on pulses tone-on pulses tone-on pulses tone-on pulses tone-on pulses tone-on pulses tone-on pulses tone-on pulses I Backward signals I I Proceed-to-send (optional) I continuous tone-off I Address-complete (optional) single
16、 tone-on pulse I Proceed-to-send-on-recall (optional) I single tone-on puise I I Reconnect (optional) I double tone-on-pulse I Table 1 (T/CS 49-02). Decadic pulsing interregister signal codes. Adjacent address signals are separated by an inter-digit pause (IDP). This pause is a function of the type
17、of PABX concerned and the source of the digits, e.g. whether generated within the outgoing PABX or repeated by the PABX under the control of a dial. The inter-digit pause, which will differ depending upon the Administration concerned and the type of PABX, is not specified in this Recommendation and
18、must be mutually agreed upon by the parties involved. During the inter-digit pause the through-connection of the backward speech path is re-established. Signals having the same coding shall be distinguished by their position in the sequence of the signalling procedure . Edition of May 15, 1986 CEPT
19、T/CS*47-02*E 2326414 0004882 2 Speed (pulses per second) Break pulse Duration (ms) TICS 49-02 E Page 3 7 9 11 12 Min Max Min Max Min Max Min Max 45 112 45 81 45 61 45 52 Speed (pulses per second) Break pulse Duration (ms) Edition of May 15, 1986 I 9 11 12 Min Max Min Max Min Max Min Max 35 122 35 91
20、 35 71 35 62 i CEPT T/CS*4-O2*E 232b4l14 OOOY883 4 TICS 49-02 E Page 4 3. REGISTER-RECALL SIGNALLING Register-recall provides the means for control information transfer after termination of the call Set-up. Register-recall can, as forward or backward recall, be initiated in either direction, regardl
21、ess of the direction of the original call Set-up. When the register at the destination PABX is required to be recalled, the forward or backward service- request-recall signal shall be sent. The service-request-recall signal shall not recall the registers of transit switches. When the transit registe
22、r is required to be recalled, the forward- or backward-link-recall signal shall be sent to the adjacent transit switch. Upon recognition of a register-recall signal, the proceed-to-send-on-recall signal is sent to indicate that the responding PABX is ready for System L1 decadic pulsing interregister
23、 signalling. Upon recognition of a register recall signal, the reconnect signal is sent to indicate that the responding PABX - does not allow a register-recall to be extended, or - wishes the initiating PABX to switch-through the connection. 4. SIGNAL TRANSMISSION REQUIREMENTS ON THE LINE 4.1. Signa
24、l sender and receiver The signal transmission requirements on the line which are specified in Recommendation T/CS 49-01 i apply for all signals. 4.2. Splitting and spill-over CCITT Recommendation 4.25 3 and Recommendation T/CS 49-0 1 apply. Through-transmission shall not be restored during the tone-
25、off periods of address signals. REFERENCES Recommendation TICS 49-01. System LI line signalling over international interprivate automatic branch exchange lines. Recommendation T/CS 49-03. System LI decadic pulsing call control signalling procedures. CCITT Recommendation 4.25. Splitting arrangements
26、and signal recognition times in “in band” signalling systems. CCITT Recommendation G. 17 1. Transmission characteristics of leased circuits formingpart of aprivate telephone network. CCITT Recommendations M. 1010 to M. 1060. International leased circuits. Recommendation T/CS 4 1-01. Signal and signalling message names and meanings. a Edition of May 15, 1986
