Active/Standby 120-Ohm Twisted Pair Cable

The active/standby 120-ohm twisted pair cable is a type of E1/T1 cable. The number of active/standby 120-ohm twisted pair cables to be configured depends on site requirements. It transmits E1/T1 signals. It is used to connect the GEIUA/GEIUB/GEIUP/GEIUT/GEHUB/GEPUG to the DDF or other NEs.

Cable Structure

Figure 1 shows the active/standby 120-ohm twisted pair cable.

Figure 1 Active/standby 120-ohm twisted pair cable

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

As shown in Figure 1, W3 and W4 are 120-ohm twisted pair cables; W1 and W2 are 100-ohm twisted pair cables; X1 and X2 are DB44 connectors, which should be connected to the active and standby boards.

Table 1 describes the mapping between the active/standby 120-ohm twisted pair cable and the pins of the DB44 connector.

**Table 1** Mapping between the 120-ohm twisted pair cables and the pins of the DB44 connector
X1	W3		Color	X1	W4		Color
Pin of DB44 Connector	Signal	Identifier of Twisted Pair Wire	Color	Pin of DB44 Connector	Signal	Identifier of Twisted Pair Wire	Color
38	Ring/R-	R1	Blue	15	Ring/R-	T1	Blue
23	Tip/R+	R1	White	30	Tip/R+	T1	White
37	Ring/R-	R2	Orange	14	Ring/R-	T2	Orange
22	Tip/R+	R2	White	29	Tip/R+	T2	White
36	Ring/R-	R3	Green	13	Ring/R-	T3	Green
21	Tip/R+	R3	White	28	Tip/R+	T3	White
35	Ring/R-	R4	Brown	12	Ring/R-	T4	Brown
20	Tip/R+	R4	White	27	Tip/R+	T4	White
34	Ring/T-	R5	Gray	11	Ring/T-	T5	Gray
19	Tip/T+	R5	White	26	Tip/T+	T5	White
33	Ring/T-	R6	Blue	10	Ring/T-	T6	Blue
18	Tip/T+	R6	Red	25	Tip/T+	T6	Red
32	Ring/T-	R7	Orange	9	Ring/T-	T7	Orange
17	Tip/T+	R7	Red	24	Tip/T+	T7	Red
31	Ring/T-	R8	Green	8	Ring/T-	T8	Green
16	Tip/T+	R8	Red	7	Tip/T+	T8	Red
Shell	Outer Braid of Whole Cable			Shell	Outer Braid of Whole Cable

NOTE:

In Table 1, either R- and R+ or T- and T+ stand for a pair of transmission and reception signals.

Table 2 describes the signals listed in Table 1.

**Table 2** Pins at both ends of the twisted pair cable
Signal Label	Bearing Media
Ring/R-	One wire of a twisted pair transmitting E1/T1 signals to the BSC
Tip/R+	One wire of a twisted pair transmitting E1/T1 signals to the BSC
Ring/T-	One wire of a twisted pair transmitting E1/T1 signals from the BSC
Tip/T+	One wire of a twisted pair transmitting E1/T1 signals from the BSC

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
Twisted Pair Cable W2		Remarks	Twisted Pair Cable W1		Remarks
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 120-ohm twisted pair cable are fixed to the active and standby boards (GEIUA/GEIUB/GEIUP/GEIUT/GEHUB/GEPUG). The other end of the active/standby 120-ohm twisted pair cable is connected to the DDF, and then to other NEs through a transmission device. Alternatively, the other end of the active/standby 120-ohm twisted pair cable is directly connected to an NE.

Figure 2 shows the installation position of the active/standby 120-ohm twisted pair cable.

Figure 2 Installation position of the active/standby 120-ohm twisted pair cable