An El cable has a resistance of 75 ohm or 120 ohm. 75-ohm El cable are the same type with the RJ-45 LAN cable.

The statement is incorrect for two primary reasons. First, E1 interfaces that use 75-ohm impedance are specified for use with coaxial cables, typically terminated with BNC connectors. In contrast, standard LAN cables that use RJ-45 connectors are twisted-pair cables. Second, standard Ethernet LAN cables (like Category 5e/6) have a characteristic impedance of 100 ohms, not 75 ohms. While E1 interfaces can also use 120-ohm balanced twisted-pair cables (which may use RJ-45 connectors), the assertion that a 75-ohm E1 cable is the same type as an RJ-45 LAN cable is fundamentally incorrect due to differences in cable construction (coaxial vs. twisted-pair) and impedance (75 ohm vs. 100 ohm).

The statement is presented as True, which is incorrect. It conflates two distinct types of E1 cabling and incorrectly equates one of them with standard Ethernet cabling. The physical and electrical characteristics of a 75-ohm coaxial E1 cable and a 100-ohm twisted-pair LAN cable are different, making them not the "same type."

1. Huawei AR G3 Series Routers Documentation: In the hardware description for E1/T1 interface cards

Huawei specifies the cable types for different impedances. For example

the documentation for the "2E1-F Flexible Card" explicitly states: "The E1-F interface can be set to the 75-ohm unbalanced mode or 120-ohm balanced mode... The 75-ohm E1 cable is a coaxial cable with 75-ohm characteristic impedance... The 120-ohm E1 cable is a shielded twisted pair cable with 120-ohm characteristic impedance." This confirms that 75-ohm E1 uses coaxial cable

not the twisted-pair type used for LANs.

Source: Huawei AR1200 Series Enterprise Routers Hardware Description

Section "Cards > 2E1-F/2E1-H/4E1-F/4E1-H/8E1-F/8E1-H Flexible Card".

2. ITU-T Recommendation G.703: This is the international standard that defines the physical and electrical characteristics for digital interfaces

including E1. It is the definitive source for these specifications.

Source: ITU-T Recommendation G.703

"Physical/electrical characteristics of hierarchical digital interfaces

" Section 6

"Interface at 2048 kbit/s."

Specifics: Section 6.2 defines the 120 Ω interface for use with a "symmetric pair" (twisted pair). Section 6.3 defines the 75 Ω interface for use with a "coaxial pair." This standard clearly separates the two impedance values by their required cable construction.

3. ANSI/TIA-568-C.2 Standard: This standard defines the specifications for balanced twisted-pair telecommunications cabling and components

which includes the common RJ-45 LAN cables.

Source: ANSI/TIA-568-C.2

"Balanced Twisted-Pair Telecommunications Cabling and Components Standard."

Specifics: Section 6.4

"Transmission Requirements for 100 Ω Balanced Twisted-Pair Cabling

" specifies that Category 3

5e

6

and 6A cables must have a nominal characteristic impedance of 100 ohms. This directly contradicts the claim that a standard LAN cable is a 75-ohm type.