CAB-X21 MT and CAB-X21 FC Serial Cable Specifications

Introduction

This document explains the technical and cable specifications of the CAB-X21MT and CAB-X21FC serial cables.

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

This document is not restricted to specific software and hardware versions.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Conventions

For more information on document conventions, see the Cisco Technical Tips Conventions.

X.21 Speed and Distance Limitations

The table below lists the different X.21 speed and distance limitations.

Data Rate (Baud)	Distance (Feet)	Distance (Meters)
2400	4,100	1,250
4800	2,050	625
9600	1,025	312
19200	513	156
38400	256	78
56000	102	31
T1	50	15

CAB-X21MT Serial Cable and Assembly

The cable gender for the CAB-X21MT serial cable (part number 72-0789-01) is Male DB-60 to Male DB-15, mode - DTE.

Note: The cable itself identifies the Cisco router as a DTE or DCE device to other devices in the network; for this reason, it is important to select the correct product number from the table below.

The CAB-X21MT serial cable is used in the Cisco 7000 family, Cisco 4000 series, Cisco 3600 series, Cisco 2500 series, Cisco 1600 series, Cisco access servers, and AccessPro PC cards. This cable has a male DB-60 connector on the Cisco end and a male DB-15 connector on the network end.

X.21 DTE Cable Pinouts (DB-60 to DB-15)

The table below shows the X.21 DTE cable pinouts (DB-60 to DB-15).

Note: The arrows indicate signal direction:

• ---> indicates DTE to DCE

• <--- indicates DCE to DTE

60 Pin1	Signal	Description	Direction	15 Pin	Signal
J1-48 J1-47	GND MODE_2	Shorting Group	--	--	--
J1-51 J1-52	GND MODE_DCE	Shorting Group	--	--	--
J1-46	Shield_GND	Single	--	J2-1	Shield GND
J1-11 J1-12	TxD/RxD+ TxD/RxD-	Twisted pair no. 3	---> --->	J2-2 J2-9	Transmit+ Transmit-
J1-9 J1-10	RTS/CTS+ RTS/CTS-	Twisted pair no. 2	---> --->	J2-3 J2-10	Control+ Control-
J1-28 J1-27	RxD/TxD+ RxD/TxD-	Twisted pair no. 6	<--- <---	J2-4 J2-11	Receive+ Receive-
J1-1 J1-2	CTS/RTS+ CTS/RTS-	Twisted pair no. 1	<--- <---	J2-5 J2-12	Indication+ Indication-
J1-26 J1-25	RxC/TxCE+ RxC/TxCE-	Twisted pair no. 5	<--- <---	J2-6 J2-13	Timing+ Timing-
J1-15 Shield	Control_GND --	Twisted pair no. 4	-- --	J2-8 Shield	Control_GND --

¹Any pin not referenced is not connected.

CAB-X21FC Serial Cable and Assembly

The cable gender for the CAB-X21FC serial cable (part number 72-0790-01) is Male DB-60 to Female DB-15, mode - DCE.

The CAB-X21FC serial cable is used in the Cisco 7000 family, Cisco 4000 series, Cisco 3600 series, Cisco 2500 series, Cisco 1600 series, Cisco access servers, and AccessPro PC cards. This cable has a male DB-60 connector on the Cisco end and a female DB-15 connector on the network end.

X.21 DCE Cable Pinouts (DB-60 to DB-15)

The table below shows the X.21 DCE cable pinouts (DB-60 to DB-15).

Note: The arrows indicate signal direction:

• ---> indicates DTE to DCE

• <--- indicates DCE to DTE

60 Pin1	Signal	Description	Direction	15 Pin	Signal
J1-48 J1-47	GND MODE_2	Shorting Group	--	--	--
J1-46	Shield_GND	Single	--	J2-1	Shield GND
J1-28 J1-27	RxD/TxD+ RxD/TxD-	Twisted pair no. 6	<--- <---	J2-2 J2-9	Transmit+ Transmit-
J1-1 J1-2	CTS/RTS+ CTS/RTS-	Twisted pair no. 1	<--- <---	J2-3 J2-10	Control+ Control-
J1-11 J1-12	TxD/RxD+ TxD/RxD-	Twisted pair no. 3	---> --->	J2-4 J2-11	Receive+ Receive-
J1-9 J1-10	RTS/CTS+ RTS/CTS-	Twisted pair no. 2	---> --->	J2-5 J2-12	Indication+ Indication-
J1-24 J1-23	TxC/RxC+ TxC/RxC-	Twisted pair no. 4	---> --->	J2-6 J2-13	Timing+ Timing-
J1-15 Shield	Control_GND --	Twisted pair no. 5	-- --	J2-8 Shield	Control_GND --

¹Any pin not referenced is not connected.

Related Information

• Technical Support - Cisco Systems