Active/Standby 75-Ohm Coaxial Cable

The active/standby 75-ohm coaxial cable is a type of E1/T1 cables. The number of active/standby 75-ohm coaxial cables to be configured depends on site requirements. It transmits E1 signals. It is used to connect the GEIUA/GEIUB/GEIUP/GEIUT/GEHUB/GEPUG to the DDF or other NEs.

Cable Structure

The active/standby 75-ohm coaxial cable has 2x8 wires. That is, two active/standby 75-ohm coaxial cables form one group and each cable contains eight micro coaxial cables. The 16 micro coaxial cables bear eight E1 RX and TX links.

Figure 1 shows the active/standby 75-ohm coaxial cable.

Figure 1 Active/standby 75-ohm coaxial cable

(1) DB44 connector	(2) Shell (metal shell of the DB44 connector)
(3) Label 1 (identifying one coaxial cable)	(4) Main label (identifying the BOM code, version, and information about the cable manufacturer)
(5) Label 2 (identifying one coaxial cable)

As shown in Figure 1, W3 and W4 are 75-ohm coaxial cables; W1 and W2 are 100-ohm twisted pair cables; X1 and X2 are DB44 connectors, which should be connected to the active/standby GEIUA/GEIUB/GEIUP/GEIUT/GEHUB/GEPUG.

Table 1 describes the mapping between the active/standby 75-ohm coaxial cable and the pins of the DB44 connector.

**Table 1** Mapping between the micro coaxial cables and the pins of the DB44 connector
X1	W3		Remarks	X1	W4		Remarks
Pin of DB44 Connector	Signal	Micro Coaxial Cable	Remarks	Pin of DB44 Connector	Signal	Micro Coaxial Cable	Remarks
38	Ring	1	R1	15	Ring	1	T1
23	Tip	1	R1	30	Tip	1	T1
37	Ring	2	R2	14	Ring	2	T2
22	Tip	2	R2	29	Tip	2	T2
36	Ring	3	R3	13	Ring	3	T3
21	Tip	3	R3	28	Tip	3	T3
35	Ring	4	R4	12	Ring	4	T4
20	Tip	4	R4	27	Tip	4	T4
34	Ring	5	R5	11	Ring	5	T5
19	Tip	5	R5	26	Tip	5	T5
33	Ring	6	R6	10	Ring	6	T6
18	Tip	6	R6	25	Tip	6	T6
32	Ring	7	R7	9	Ring	7	T7
17	Tip	7	R7	24	Tip	7	T7
31	Ring	8	R8	8	Ring	8	T8
16	Tip	8	R8	7	Tip	8	T8
Shell	Outer Braid of Whole Cable			Shell	Outer Braid of Whole Cable

NOTE:

As listed in Table 1, T1 indicates the first-route TX link, and R1 indicates the first-route RX link. Similarly, RN indicates the Nth-route RX link, and TN indicates the Nth-route TX link.

Table 2 describes the signals of the micro coaxial cables listed in Table 1.

**Table 2** Mapping between the signals and the bearing media
Signal Label	Bearing Media
Ring	Shielding layer of the coaxial cable
Tip	Wire of the coaxial cable

Table 3 describes the mapping between the 100-ohm twisted pair cables (W1 and W2) and the pins of the DB44 connector.

**Table 3** Mapping between the twisted pair cables and the pins of the DB44 connector
W2			W1
Pin of X1 Connector	Pin of X2 Connector	Remarks	Pin of X1 Connector	Pin of X2 Connector	Remarks
38	38	PAIR	15	15	PAIR
23	23	PAIR	30	30	PAIR
37	37	PAIR	14	14	PAIR
22	22	PAIR	29	29	PAIR
36	36	PAIR	13	13	PAIR
21	21	PAIR	28	28	PAIR
35	35	PAIR	12	12	PAIR
20	20	PAIR	27	27	PAIR
34	34	PAIR	11	11	PAIR
19	19	PAIR	26	26	PAIR
33	33	PAIR	10	10	PAIR
18	18	PAIR	25	25	PAIR
32	32	PAIR	9	9	PAIR
17	17	PAIR	24	24	PAIR
31	31	PAIR	8	8	PAIR
16	16	PAIR	7	7	PAIR
Shell	Shell	Braid	Shell	Shell	Braid

NOTE:

As listed in Table 3, PAIR indicates a pair of twisted pair cables, and Braid indicates the outer shielding layer of the twisted pair cable.

Installation Position

The two DB44 connectors at one end of the active/standby 75-ohm coaxial cable are fixed to the active and standby boards (GEIUA/GEIUB/GEIUP/GEIUT/GEHUB/GEPUG. The other end of the 75-ohm active/standby coaxial cable is connected to the DDF, and then to other NEs through a transmission device. Alternatively, the other end of the 75-ohm active/standby coaxial cable is directly connected to an NE.

Figure 2 shows the installation position of the active/standby 75-ohm coaxial cable.

Figure 2 Installation position of the active/standby 75-ohm coaxial cable