Cisco EIA/TIA-449 (RS-449) DTE

EIA/TIA-449 DTE Cable Pinout (DB-60 to DB-37)

The Cisco EIA/TIA-449 DTE cable connects the 60-pin high-density DB-60 connector on Cisco 4000, 4500, and 4700 series routers to a 37-pin D-sub (DB-37) network device. EIA/TIA-449 (RS-449) is a general-purpose serial interface standard using RS-422 balanced differential signalling for primary data and clock circuits and RS-423 unbalanced signalling for control circuits, supporting throughput up to 10 Mbps. It was designed as a higher-performance replacement for EIA/TIA-232 and is related to the V.36 modem standard, though in practice it was largely superseded by EIA/TIA-530, which offers equivalent electrical performance in a smaller DB-25 housing. The DTE cable carries a male DB-37 plug at the network end; the router end uses the DB-60 connector common to all Cisco classic WAN serial cables, with shorting pins on the DB-60 selecting the interface type and mode.

Notes

• Arrows indicate signal direction: → indicates DTE to DCE, and ← indicates DCE to DTE.
• (1) Any pin not referenced is not connected.
• The DB-60 shorting group pins (MODE_0, MODE_1, GND, MODE_DCE in the J1-46–J1-52 range) determine which serial interface standard and which DTE/DCE mode is active; for EIA/TIA-449 DTE the appropriate pins are shorted by the cable itself.
• Primary data and clock signals use RS-422 balanced differential pairs; some link-management control signals use RS-423 unbalanced signalling.
• The network end of the DTE cable carries a male DB-37 plug; the corresponding DCE cable (CAB-449FC) carries a female DB-37 receptacle.
• All signals are transmitted as twisted pairs on the DB-60 side, numbered as listed in the Description column.

Signals

• SD+/SD- — Send Data (positive/negative); balanced differential pair carrying serial data transmitted from the DTE (router) to the DCE network device (DB-37 pins 4/22).
• ST+/ST- — Send Timing; clock signal provided by the DCE to synchronise DTE transmit data (DB-37 pins 5/23).
• RD+/RD- — Receive Data; balanced differential pair carrying serial data received by the DTE from the DCE (DB-37 pins 6/24).
• RS+/RS- — Request to Send; DTE asserts this control signal to request permission to transmit (DB-37 pins 7/25).
• RT+/RT- — Receive Timing; clock signal provided by the DCE for synchronisation of received data (DB-37 pins 8/26).
• CS+/CS- — Clear to Send; DCE asserts this signal in response to RS, granting the DTE permission to transmit (DB-37 pins 9/27).
• LL — Local Loopback; DTE-asserted control signal used for local loopback testing of the DCE (DB-37 pin 10).
• DM+/DM- — Data Mode; DCE indicates that it is ready and in a data communication mode, equivalent to DSR in EIA/TIA-232 (DB-37 pins 11/29).
• TR+/TR- — Terminal Ready; DTE signals readiness to the DCE, equivalent to DTR in EIA/TIA-232 (DB-37 pins 12/30).
• RR+/RR- — Receiver Ready; DCE indicates that a received carrier signal is present, equivalent to DCD in EIA/TIA-232 (DB-37 pins 13/31).
• TT+/TT- — Terminal Timing; clock signal provided by the DTE to the DCE for transmit synchronisation (DB-37 pins 17/35).
• SG — Signal Ground; common reference ground for all signal circuits (DB-37 pin 19).
• RC — Receive Common; return path reference for unbalanced (RS-423) control circuits (DB-37 pin 20).
• SC — Send Common; return path reference for unbalanced (RS-423) send-direction control circuits (DB-37 pin 37).
• Shield GND — Cable shield connected to chassis/frame ground (DB-37 pin 1).

References

• Serial Cable Connection Guide (Document ID: 12219)

Category:Serial Cables