Chapter 19: Dual optical + 21xE1 S1.1-2-LC/E1-21 Module

Dual optical + 21xE1 S1.1-2-LC/E1-21 Module

19.1 Module Description

The module contains two optical STM-1 short-haul interfaces and 21 E1 interfaces as shown in Figure 19-1. The main functions of the module are O/E- E/O conversion and SDH multi-/demultiplexing with VC-12, VC3 and VC-4 granularity of the STM-1 traffic and VC-12 mapping/demapping demultiplexing of the E1 traffic. See 5.1.1 Multiplexing Structure and Mapping modes, page 5-1. The module supports both transparent E1 data transmission acc. to ITU-T Rec. G.703 as well as the NT functionality of ISDN PRA according to ETSI 300 233. One high density LFH type connector is used to interface the 21 E1's and a dual fiber LC connector, one fiber in each direction, is used on the two STM1 interfaces.

Figure 19-1 STM-1 S1.1-2-LC/E1-21

Module

19.1.1 Power Consumption

The module power consumption is 15 W.

19.2 External STM-1 S-1.1 Interface

The optical STM1 interfaces are short haul interfaces, according to ITU-T Rec. G.957, S-1.1, bi-directional transmission on two Single Mode (SM) fibres.

The module can also be used for transmission on Multi Mode (MM) fibres, see Example of Cable Planning, STM-1 S-1.1 interface.

19.2.1 Connector Type

The physical connector is a LC connector.

19.2.2 Optical Budget

The S-1.1 Interface Optical Budget is listed in Table 19-1.

Table 19-1 S-1.1 Interface Optical Budget
Parameter	Value
Type of fiber: SM acc. ITU-T Rec. G.652 (See Note below)	10/125 痠
Modulation rate on optical line	155 520 kbit/s
Wavelength range	1261 - 1360 nm
Transmitter at reference point S
Source type	MLM
Spectral characteristics (max. RMS width)	7.7 nm
Mean launched power (max.)	-8 dBm
Mean launched power (min.)	-15 dBm
Min. extinction ratio	8.2 dB
Optical path between S and R
Attenuation range	0 - 12 dB
Max. tolerable dispersion	96 ps/nm
Min. optical return loss	NA
Max. discrete reflectance between S and R	NA
Receiver at reference point R
Min. sensitivity (BER < 1 in 1010)	-28 dBm
Min. overload	-8 dBm
Max. optical path penalty	1 dB
Max. reflectance at R	NA

Note The module can also be used for transmission on Multi Mode fiber, see Example of Cable Planning, STM-1 S-1.1 interface.

19.2.3 Compliance

The Optical S-1.1 Interface Compliance is listed in Table 19-2.

Table 19-2 Optical S-1.1 Interface Compliance
Standard	Comment
ITU-T G.652	Type of optical fiber
ITU-T G.707	Optical line signal
ITU-T G.783	RX pull-in and hold range
ITU-T G.813	Optical output jitter
ITU-T G.825	Optical input jitter
ITU-T G.957	Optical spectrum Optical output power Optical eye diagram Optical extinction ratio
ITU-T G.958	Input jitter measurement
ITU-T G.651	Multi Mode fiber specification 50/125 痠
IEC/EN 60793-2-10	Optical fibres -- Part 2-10: Product specifications - Sectional specification for category A1 multimode fibres

19.2.3.1 Optical Rx Power Monitoring

The optical input power of the Rx interface is monitored and can be read from the Cisco EdgeCraft terminal.

19.3 External E1 Interface

This section list related external E1 interface characteristics.

19.3.1 Connectors

The connector is a high density LFH connector. See 14.2.1 32XE1 LFH - LFH Cable, page 14-5 for details.

19.3.2 Pinout

The high density LFH connector pin-out is given in Table 19-3.

Table 19-3 Pin-out high density LFH connector
Pin	Signal	Pin	Signal	Pin	Signal	Pin	Signal
1		41	RxD2-	81		121	RxD4-
2		42	RxD2+	82		122	RxD4+
3	GND	43	GND	83	GND	123	GND
4		44	TxD2-	84		124	TxD4-
5		45	TxD2+	85		125	TxD4+
6		46	TxD6-	86		126	TxD8-
7		47	TxD6+	87		127	TxD8+
8	GND	48	GND	88	GND	128	GND
9		49	RxD6-	89		129	RxD8-
10		50	RxD6+	90		130	RxD8+
11	RxD21-	51	RxD10-	91		131	RxD12-
12	RxD21+	52	RxD10+	92		132	RxD12+
13	GND	53	GND	93	GND	133	GND
14	TxD21-	54	TxD10-	94		134	TxD12-
15	TxD21+	55	TxD10+	95		135	TxD12+
16	TxD17-	56	TxD14-	96	TxD19-	136	TxD16-
17	TxD17+	57	TxD14+	97	TxD19+	137	TxD16+
18	GND	58	GND	98	GND	138	GND
19	RxD17-	59	RxD14-	99	RxD19-	139	RxD16-
20	RxD17+	60	RxD14+	100	RxD19+	140	RxD16+
21	RxD13-	61	RxD18-	101	RxD15-	141	RxD20-
22	RxD13+	62	RxD18+	102	RxD15+	142	RxD20+
23	GND	63	GND	103	GND	143	GND
24	TxD13-	64	TxD18-	104	RxD15-	144	TxD20-
25	TxD13+	65	TxD18+	105	RxD15+	145	TxD20+
26	TxD9-	66		106	TxD11-	146
27	TxD9+	67		107	TxD11+	147
28	GND	68	GND	108	GND	148	GND
29	RxD9-	69		109	RxD11-	149
30	RxD9+	70		110	RxD11+	150
31	RxD5-	71		111	RxD7-	151
32	RxD5+	72		112	RxD7+	152
33	GND	73	GND	113	GND	153	GND
34	TxD5-	74		114	RxD7-	154
35	TxD5+	75		115	RxD7+	155
36	TxD1-	76		116	TxD3-	156
37	TxD1+	77		117	TxD3+	157
38	GND	78	GND	118	GND	158	GND
39	RxD1-	79		119	RxD3-	159
40	RxD1+	80		120	RxD3+	160

19.3.3 Patch Panels

Two types of patch panels are available for patching the 21 E1's interface. See 14.2 Patch Panels, page 14-5 for details.

Note When the LFH connector/Patch panels are used together with the STM-1 S1.1-2-LC/E1-21 module, only the first 21 ports are used.

Warning This interface is considered SELV circuit. Avoid connecting this interface to TNV circuits. The cables must not run with power cables, Network cables, or any other cables which are not connected to SELV circuits. The electrical cables must not exit the building. If cables are connected to an equipment which contains not SELV circuits, proper insulation between the ONS15305 E1 cables interface and the other equipment interfaces must be provided.

19.3.4 Compliance

The Multi-Interface E1 compliance is given in Table 19-4.

Table 19-4 Multi-Interface E1 Compliance
Standard	Comment
ETS 300 011	Impedance towards ground Tolerable longitudinal voltage
ETS 300 126	Output signal balance
ITU-T G.703	Cable attenuation Input reflection loss Input port immunity against reflection Output pulse mask
ITU-T G.783	Output jitter in the absence of input jitter Output combined jitter
ITU-T G.823	Max. tolerable input jitter

19.4 Example of Cable Planning, STM-1 S-1.1 interface

Typical cable parameters are described in Table 19-5.

Table 19-5 Typical Cable Parameters


Cable Loss, according to ITU-T Rec. G.957	Single Mode fiber Acc. to ITU-T G.652	Multi Mode fiber 50/125 um Acc. to ITU-T G.651	Multi Mode fiber 62.5/125 um Acc. to IEC/EN 60793-2-10
fiber Cable Attenuation Cable Margin (Mc) Loss in Optical Distribution Frame	0.5 dB/km Incl. in fiber att Incl. in fiber att.	1.0 dB/km 3 dB 1 dB	1.0 dB/km 3 dB 1 dB


Cable Dispersion:
Maximum Chromatic Dispersion Coefficient	5.5 ps/nm*km	6 ps/nm*km	6 ps/nm*km
Modal bandwidth	-	800 MHz*km ¹	500 MHz*km ²
Overall bandwidth	-	80 MHz	80 MHz

¹Modal bandwidth for Overfilled launch (OFL).

²Modal bandwidth for Overfilled launch (OFL).

Typical Link Spans are described in Table 19-6.

Table 19-6 Typical Link Spans


Type of fiber		Loss Limited Span	Dispersion Limited Span	Overall Link Span	Notes
Two-fiber	SM	24 km	47 km	24 km
	MM 50 mm	13 km	10 km	10 km	¹, ²
	MM 62.5 mm	13 km	6 km	6 km	³

¹Offset launch with mode-conditioning patchcord according to IEEE Std. 802.3 1998 edition.

²By using a MM fiber like GIGAlite™ II, dispersion limited spans can be extended to 15km (50/125mm) and 9 km (62.5/125 mm) without the need of a mode-conditioning patchcord.

³See 1 and 2 above.

Center launch with SM patch cord connected directly to the MM fiber gives potentially much higher bandwidths than the OFL bandwidths (several GHz/km) as only a few central modes are launched.

However, MM fibres can contain central index distortions, which can give rise to bandwidth collapse with small offsets from center. Both center launch and offset launch with FP laser creates underfilled excitation of the MM fiber. Offset launch is less vulnerable to mode coupling distortions due to the higher number of modes being exited. Underfilled excitations generally gives higher bandwidths than OFL.

Recommendation

Center launch i.e. SM patchcord from 2xS-1.1-LC, is likely to achieve transmission distances at least as given in the table for most MM Fiber cables. Use of mode conducting cord for offset launch, is preferred when quality of MM fiber plant is unknown.

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