10/100/1000BaseT to 1000M SFP Web Smart Fiber Media Converter

  • Comply with IEEE 802.3, 802.3u, 802.3ab and 802.3z
  • Build in Link Loss Forwarding Technology
  • DIP switch for Auto negotiation, Half/ Full Duplex and LLF, Converter mode
  • Support Q-in-Q Double Tag VLAN, DHCP Client, SNMP v1 and v2c
  • Slide in 16-slot converter chassis


Datasheet   Manual


Lantech CM-121 is a 10/100/1000 Base T to Gigabit web smart fiber media converter with managed function which including 801.q VLAN, SNMP v1/ v2c and DHCP. The converter can be managed through Web and SNMP interface. Lantech CM-121 is designed to extend the transmitting distance of cooper to optical-fiber network.

Lantech CM-121 is fully compliant with IEEE 802.3, 802.3u, 802.3ab & 802.3z standards and supports 8 DIP switches to adjust transmitting mode and Link Loss Forwarding (LLF) feature. The practical feature of LLF is essential for media converter to alert MIS about the one end connection lost. It will cut off transmission between two converters immediately when one end is disconnected.

Lantech CM-121 supports Jumbo frame up to 9K Bytes on switch mode so it is suitable for the extension of backbone network where could have jumbo packets on the network.

CM-121 can be slide into a 16-slots chassis which RPS option (MC-116-RPS) to be centralized and rack mountable.


  • Fully complies with IEEE 802.3, 802.3u, 802.3ab, 802.3z Standards
  • 10/100/1000T to gigabit  web smart Fiber (Mini GBIC)  Media converter
  • Built in Link Loss Forwarding Technology
  • 10/100/1000T support Auto MDI/MDI-X
  • Support Selectable ISP Ethernet Tag Type
  • Support Flow Control
  • Jumbo frame 9K Bytes
  • Q-in-Q Double Tag configuration
  • Support Bandwidth Control
  • DHCP Client
  • SNMP/ Web Managed interface
  • Support SNMP v1 and v2c
  • HTTP Firmware Upgrade


Hardware Specification


IEEE 802.3 10Base-T
IEEE 802.3u 100Base-TX
IEEE 802.3ab 1000Base-T
IEEE 802.3z 1000Base-X
IEEE 802.3x flow Control


10/100/1000Base-T RJ-45 Port x 1
1000Base-X SFP slot x 1

Switch architecture

Store and Forward

MAC address table


Jumbo Frame

9K Bytes

Memory buffer:


Link Loss Forward

100/1000T =>Fiber: If TX port link down, then converter will forced fiber to link down.
Fiber =>100/1000T: If Fiber port link down, the media converter will forced 100/1000T port to link down.

Power Adopter

Power: Output DC 5V, 1.6A
Power Input: AC 100~240 V

Power Consumption



Operation Temperature.: 0°C to 50°C
Storage Temperature: -20° ~ 60℃
Operation Humidity: 5% to 90% (Non-condensing)


Power, FDX, Status, Speed, FO Link/Act, TX Link/Act

DIP Switch

DIP Switch 1: UTP Auto-Nego ; Disable/ Enable
DIP Switch 2: Manual TX Data Rate: 10 /100M
DIP Switch3: Manual TX Data Rate: 10/100M or 1000M
DIP Switch4: Flow Control ; Disable/ Enable
DIP Switch5: Fiber Auto-Nego ; Force / Enable
DIP Switch6: Reserve
DIP Switch7 : LLF (Link Loss Forwarding)  Disable/Enable
DIP Switch 8: RJ-45port Configuration ;
from SW/ from DIP


Module: 71mm(W)X94mm(D)X26mm(H)

EMI & Safety

FCC Class A, CE


2 years

Software Specification


Web UI management
SNMP Management

Firmware update

HTTP firmware upgradable


IEEE 802.1Q tag VLAN
VLAN Group: There are 16 VLAN Groups  
VID: 1~4094


Support SNMP v1/v2c
Support power down trap

Bandwidth Control

Ingress / egress from 64 ~ 512000Kbps

Loopback Test

send packet number :1~255, default:100


Support DHCP client


P/N Model name Description
8421-250 CM-121 10/1000M BASE-T to Gigabit Web Smart Fiber Media Converter w/LLF design
8420-008 MC-116-RPS-P1AC 16 Slots Universal Media Converter Rack 19-inch (2U), with 1 AC power
8420-009 MC-116-RPS-P1DC 16 Slots Universal Media Converter Rack 19-inch (2U), with 1 DC power
EOTH000670 MC-116-RPS-AC POWER Slide-in AC Power Module for MC-116-RPS
EOTH000671 MC-116-RPS-DC-POWER Slide-in DC Power Module for MC-116-RPS


Model name Description Model name Description
8330-162X MINI GBIC 1000SX (LC/0.5km) Transceiver 8330-188 LTSFP-1000BX-10KM Transceiver (WDM 1310)
8330-163X MINI GBIC 1000SX2 (LC/2km) Transceiver 8330-189 LTSFP-1000BX-10KM Transceiver (WDM 1550)
8330-165X MINI GBIC 1000LX (LC/10km) Transceiver 8330-186 LTSFP-1000BX-20KM Transceiver (WDM 1310)
8340-0591 MINI GBIC 1000LHX (LC/40km) Transceiver 8330-187 LTSFP-1000BX-20KM Transceiver (WDM 1550)
8330-166 MINI GBIC 1000XD (LC/50km) Transceiver 8330-180 LTSFP-1000BX-40KM Transceiver (WDM 1310)
8330-169 MINI GBIC 1000XD (LC/60km) Transceiver 8330-182 LTSFP-1000BX-40KM Transceiver (WDM 1550)
8330-167 MINI GBIC 1000ZX (LC/80km) Transceiver 8330-181 LTSFP-1000BX-60KM Transceiver (WDM 1310)
8330-170 MINI GBIC 1000EZX (120km) Transceiver 8330-183 LTSFP-1000BX-60KM Transceiver (WDM 1550)
8330-168 MINI GBIC 1000T (100m) Transceiver 8330-184 LTSFP-1000BX-80KM Transceiver (WDM 1490)
    8330-185 LTSFP-1000BX-80KM Transceiver (WDM 1550)