Cisco Token Ring Port DB9

DE-9 female STP Token Ring port on Cisco routers and network modules; conforms to IEEE 802.5 using two 150-ohm shielded twisted pairs at 4 or 16 Mbit/s.

Updated:

Cisco Token Ring Port DB9 – 9-pin D-sub female 9 pin D-SUB female connector at the cisco router.

Cisco Token Ring Port DB9 – 9-pin D-sub male 9 pin D-SUB male connector at the cable.

The Cisco Token Ring DB-9 port is a DE-9 (commonly called DB-9) female socket found on Cisco router port adapters and network modules, such as the NM-1E1R2W and NM-1FE1R2W. It conforms to the IEEE 802.5 Token Ring standard and carries two 150-ohm shielded twisted pairs — one for receive and one for transmit — supporting both 4 Mbit/s and 16 Mbit/s Token Ring operation. The same DB-9 pinout originated with IBM PC Token Ring adapters in the mid-1980s and was subsequently adopted as the standard lobe-cable interface at the station end; the wiring concentrator (MAU) end uses IBM’s hermaphroditic Universal Data Connector. Cisco installation guides explicitly label the port a “Standard IEEE 802.5 connector.”

PinSignal
1Receive
2Ground
3+5V
4Ground
5Transmit
6Receive
7Ground
8Ground
9Transmit

Signals

  • Receive (pins 1 & 6) — differential receive pair (Ring In); one twisted pair of the IBM 150-ohm STP lobe cable, carrying data from the Token Ring wiring concentrator (MAU) to the station.
  • Transmit (pins 5 & 9) — differential transmit pair (Ring Out); the second twisted pair, carrying data from the station to the MAU.
  • Ground (pins 2, 4, 7, 8) — signal common / DC return.
  • +5V (pin 3) — DC supply; present on some adapter implementations.

Notes

  • The port is wired for a shielded lobe cable (IBM Type 1, Type 6, or Type 9 STP). Type 3 telephone-grade UTP requires a separate media filter adapter.
  • Pins 1 & 6 form one twisted pair (receive); pins 5 & 9 form the other (transmit). The remaining pins carry ground and, on some implementations, +5 V.
  • The MAU end of the lobe cable terminates in IBM’s hermaphroditic Universal Data Connector (UDC/IDC), not a DB-9.
  • On Cisco network modules with both DB-9 (STP) and RJ-45 (UTP) Token Ring ports, only one interface may be active at a time.
  • Supported speeds: 4 Mbit/s and 16 Mbit/s (IEEE 802.5).

References

Category: Networking Connectors