Connection Guide for Cisco Catalyst 3750 Series Switches

Connection Guide for Cisco Catalyst 3750 Series Switches

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Cisco catalyst 3750 series switch and FS.COM optics

Cisco Catalyst 3750 series switches impressed many network engineers in the past days when 10G back-bone at full steam. They are ideal switches for access layer in many midsize enterprises. Even now, when 40/100G are becoming the back-bone of transmission network, many companies still use Cisco Catalyst 3750 series switches at layer 3. This series can offer forwarding rates from 32G to 128G (Catalyst 3750-E switch series). This post will offer detailed information about Cisco Catalyst 3750 series switches and the connection solutions.

Cisco Catalyst 3750 Series Switches

Cisco Catalyst 3750 is a series of switches provide flexible configuration and supports converged network pattern, which makes the management and organization of the network become easier and more flexible. One of the biggest characteristics of Cisco Catalyst 3750 Switches is that they are armed with StackWise ports on their rear panel that can support Cisco StackWise technology. With StackWise technology, up to nine physical Catalyst 3750 switches can be interconnected into one logical switch with a high performance of 32G or 128G (by Catalyst 3750-E switch series). The following picture shows the rear panel of a Cisco Catalyst 3750 switch.

Cisco Catalyst 3750G-48TS rear panel

There are a variety of different configurations in Cisco Catalyst 3750 Series which can fit different applications. For example, Cisco Catalyst 3750G-12S contains 12 SFP ports, Cisco Catalyst 3750G-24TS-1U has 24 Ethernet 10/100/1000 ports plus 4 SFP uplinks in 1 rack unit (RU) height, Cisco Catalyst 3750G-48PS is armed with 48 Ethernet 10/100/1000 ports with IEEE 802.3af PoE and 4 SFP uplinks. The following picture shows the detailed ports information of Cisco Catalyst 3750G-48TS, which has 48 Ethernet 10/100/1000 ports and 4 SFP uplinks.

Cisco Catalyst 3750G-48TS front panel

Connecting Cisco Catalyst 3750 Series in Network

As mentioned that Cisco Catalyst 3750 series switches have different ports including RJ45 ports and SFP ports which can support data rate ranging from 10M to 1G. And cables and connectors used to connect the switches to the network are also different depending on the form and data rate of the ports.

10/100/1000 Ports Connections

The 10/100/1000 Ethernet ports on Cisco Catalyst 3750 switches uses standard RJ45 connectors, which are bases on copper cables (shown in the following picture). Here are some tips for selecting the related copper cables. When connecting Catalyst 3750 to workstations, servers, routers, connect a straight-through cable to an RJ45 connector on the front panel; When connecting to switches or repeaters, use a crossover cable; When connecting to 1000Base-T-compatible devices, be sure to use a twisted four-pair, Cat5 cable.

Cisco Catalyst 3750 RJ45 connection SFP Module Ports Connections

Some of the Cisco Catalyst 3750 series switches have several SFP module ports on the front panel. By using Gigabit Ethernet SFP modules, Gigabit copper or fiber optic uplinks can be built. Cisco Catalyst 3750 switches SFP ports can support a variety of SFP modules. These ports can be connected with fiber optic SFP modules like 1000Base-LX and 1000Base-SX and copper SFP modules like 1000Base-T. The following picture illustrates the connections with fiber optic SFP module port and Copper SFP module port from left to right separately.

Cisco catalyst 3750 SFP port connection

Cisco Catalyst 3750 Series Switches Cabling Solution

More related cables and modules that Cisco Catalyst 3750 switches supporting are listed in the following chart for your reference.

Port Type
Data Rate
Connectors/Modules & Cables
RJ45 Ports 10BASE-T ports  RJ-45 connectors, two-pair Cat 3, 4, or 5 unshielded twisted-pair (UTP)
10BASE-T PoE ports  RJ-45 connectors, two-pair Cat 3, 4, or 5 UTP cabling power pins 1, 2 (negative) and 3, 6 (positive)
100BASE-TX ports  RJ-45 connectors, two-pair Cat 5 UTP
100BASE-TX PoE ports  RJ-45 connectors, two-pair Cat 5 UTP, power on pins 1, 2 (negative) and 3, 6 (positive)
SFP Ports 100M GLC-GE-100FX LC duplex, MMF
GLC-FE-100LX LC duplex, SMF
GLC-FE-100BX-D LC simplex, SMF
1G GLC-SX-MM LC duplex, MMF
GLC-BX-U LC simplex, SMF
GLC-T RJ-45, Cat 5

All the above mentioned products are fully tested in FS.COM Test Center. Please contact for more details.

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