Connector and Cable Specifications

Coaxial Connector and Cable Specifications

Serial Interface Connector and Cabling

Connectors

Smart Serial Interface Module Connector

EIA/TIA-449 Connectors

Smart Serial (DCE) to Smart Serial (DTE) Cable

Smart Serial (DCE) to LFH (DTE) Cable

Console Port Connector and Cables

Connector and Cable Specifications

This appendix describes the pinouts and cabling requirements for the interfaces and cables used on the Cisco uBR910 series cable data service unit (DSU). All connectors for these interfaces are on the rear panel. (See Figure B-1.)

Figure B-1: Cisco uBR910 Series Connectors

This appendix describes the following connectors and cabling requirements:

Coaxial Connector and Cable Specifications

The Cisco uBR910 series DSU connects to the HFC cable system with a type-F, right-angle, PCB-mount connector manufactured by Amp (model number 531-40047). The body is die cast out of zinc, with a tin-lead plating. The round, center contact is made of phosphor bronze, with a tin-lead plating. The insulator is polypropylene and will accept a coaxial cable center conductor with a diameter ranging from 0.022 inch (0.056 mm) to 0.042 inch (1.07 mm).

The coaxial cable used to connect the Cisco uBR910 series DSU at the headend should be very high-quality cable because imperfections that do not visibly affect video transmissions can significantly affect digital data transmissions. In particular, poor insulation, improperly installed additional outlets, the condition and length of the cable's center conductor, and the quality of the cable can negatively affect the connectivity and performance of the Cisco uBR910 series for digital data transmission.

For example, a 5 dB reduction in signal quality for analog downstream video might cause a slight degradation of picture clarity, which might or might not be noticeable to a subscriber. However, a reduction of only 1 dB in signal quality for digital data might completely disrupt service to a Cisco uBR910 series user.

Cisco recommends that you use a headend-grade coaxial cable or a quad-shield coaxial cable with a minimum of 60% + 40% braid and double foil insulation to connect the cable modem cards to the HFC network. The center conductor must be straight and extend 1/8 inch (3.2 mm) beyond the end of the connector, and the connector should be securely crimped to the cable. The following cables are recommended:

RG-59---0.034 inch (0.86 mm) center conductor diameter
RG-59/U---0.0226 inch (0.57 mm) center conductor diameter
RG-6---0.041 inch (1.05 mm) center conductor diameter

Note All three of the coaxial cables listed can be used to connect a Cisco cable modem card to the HFC network; however, the consistent use of RG-59 cable is preferred. If you connect an RG-59 cable to a cable modem card that was previously connected using RG-6 cable, the difference in the center connector diameter might cause intermittent connectivity loss.

If you use different types of coaxial cable, the following problems can appear:

Co-channel interference---If signals at the same frequency are carried on long, parallel runs of coaxial cable, interference can occur between the signals. Higher quality cable helps to prevent this with better shielding. Co-channel interference is seen as hum or patterns in analog video channels and intermittent data loss in digital channels.
Damage to Cisco uBR910 series coaxial F-connector---The coaxial cable F-connector is designed for RG-59 or RG-6 cable and connectors. Larger cables can damage the connectors.
High signal return loss---High quality cable and correct connectors help to ensure an optimal return loss of 16 dB or higher.

Note Refer to the Cisco uBR910 Series Cable DSU Software Configuration Guide for additional configuration and site requirement information.

Serial Interface Connector and Cabling

The Cisco uBR910 series DSU supports the 1-port Smart Serial synchronous serial interface, which has the following features:

Supports the EIA/TIA-449, EIA-530, X.21, and V35 protocols, automatically selected by at the Smart Serial transition cable being used.
Compatible with the Smart Serial and LFH synchronous serial interfaces used on many Cisco access routers, such as the Cisco 1600 series, 1700 series, 2500 series, 2600 series, and 3600 series routers.
Supports rates up to 8 Mbits/sec, depending on the maximum capabilities of the access router.
Uses a 26-pin IDC connector.

Note The serial interface on the Cisco uBR910 series DSU can be connected only to a compatible serial interface on an access router that is acting as a LAN gateway. Cisco does not support connecting the Cisco uBR910 series to a public switched network or a telco device such as a PBX.

This section provides the following information:

Connectors---Displays each type of connector that is commonly used for the interfaces supported by the Cisco uBR910 series DSU, along with the pinouts for each connector.
Serial Cables---Describes the Cisco cables that connect the serial interface on the Cisco uBR910 series to Cisco routers that are using a compatible WAN interface module.

Note For the connector-to-connector pinouts for the serial transition cables, see the Cisco Modular Access Router Cable Specifications document, available on CCO and the Documentation CD-ROM.

Connectors

The type of serial cable that is required depends on the type of connectors being used on the serial interfaces and on the protocol being used. The following conventions are usually used when making a WAN connection:

The DTE device (most often the access router) typically requires a plug connector on the serial cable connecting to its serial interface. This end of the connection can be referred to as the interface card end of the connection.
The DCE device (typically the CSU/DSU or other network entry device) typically requires a receptacle connector on the serial cable connecting to its serial interface. This end of the connection is usually referred to as the network end because it connects to the wide area network.

Note The serial interface on the Cisco uBR910 series DSU should always be configured as the DCE device. The access router should be configured as the DTE device.

The network side of a serial cable can have a wide variety of connectors---the Smart Serial interface uses a 26-pin IDC connector. The interface end of the serial cable usually has one of the following connectors, depending on the serial protocol being used:

The EIA-530 interface usually requires a DB-25 connector on the network end of its serial cable.
The EIA/TIA-449 interface usually requires a DB-37 connector on the network end of its serial cable.
The X.21 interface usually requires a DB-15 connector on the network end of its serial cable.
The V.35 interface requires a 34-pin Winchester-type connector on the network end of its serial cable.

Note Although the Smart Serial interface supports the EIA/TIA-232 protocol, the Cisco uBR910 series DSU does not support EIA/TIA-232 connections because its allowable bandwidth (maximum 115 kbps, but typically much less) is insufficient for a cable network connection.

The following sections describe each type of connector.

Smart Serial Interface Module Connector

The Smart Serial synchronous router interface module uses a 26-pin IDC receptacle connector. Figure B-2 shows the connector on the Smart Serial router interface module.

Figure B-2: Smart Serial Router Interface Module

EIA/TIA-449 Connectors

EIA/TIA-449, which supports balanced (EIA-422) and unbalanced (EIA-423) transmissions, is a faster (up to 2 Mbps) version of EIA-232 that provides more functions and supports transmissions over greater distances.

The EIA/TIA-449 standard was developed to replace the EIA-232 standard, but it was not widely adopted primarily because of the large installed base of DB-25 hardware and because the larger size of the 37-pin EIA/TIA-449 connectors reduced the number of possible connectors in a given space as compared with the smaller, 25-pin EIA-232 connector.

The network end of the EIA/TIA-449 adapter cable provides a standard 37-pin D-shell connector. Figure B-3 shows the connectors used for DTE (plug connector) and DCE (receptacle connector) devices.

Figure B-3: EIA/TIA-449 Adapter Cable Connectors

V.35 Connectors

The V.35 interface was officially recommended for speeds up to 48 kbps, although it is often used successfully at 8 Mbps. The network end of the V.35 adapter cable provides a standard 34-pin Winchester-type connector. Figure B-4 shows the connectors used for DTE (plug connector) and DCE (receptacle connector) devices.

Figure B-4: V.35 Adapter Cable Connectors, Network End

Note To create a V.35 loopback connector, use a V.35 DCE cable (CAB-V35FC for the LFH interface and CAB-SS-V35FC for the Smart Serial interface) and connect pin P to pin R, pin S to pin T, pin U to pin Y, and pin W to pin AA on the V.35 connector.

X.21 Connectors

The X.21 interface uses a 15-pin connection for balanced circuits and is commonly used in the United Kingdom to connect public data networks. X.21 relocates some of the logic functions to the DTE and DCE interfaces and, as a result, requires fewer circuits and a smaller connector than EIA-232.

The network end of the X.21 adapter cable is a standard DB-15 connector. Figure B-5 shows the connectors used for DTE (plug connector) and DCE (receptacle connector) devices.

Figure B-5: X.21 Adapter Cable Connectors, Network End

EIA-530 Connectors

EIA-530, which supports balanced transmission, provides the increased functionality, speed, and distance of EIA/TIA-449, using the EIA-422 and EIA-423 electrical specifications. However, EIA-530 uses the smaller DB-25 connector used for EIA-232 instead of the 37-pin connectors used for EIA/TIA-449. Although the specification recommends a maximum speed of 2 Mbps, EIA-530 is used successfully at 4 Mbps or faster over short distances.

The EIA-530 adapter cable is available in DTE mode only. The network end of the EIA-530 adapter cable is a standard DB-25 plug commonly used for EIA-232 connections. Figure B-6 shows the DB-25 connector at the network end of the adapter cable.

Figure B-6: EIA-530 Adapter Cable Connector, Network End

Serial Cables

The Smart Serial synchronous router interface module can be connected to access routers running a variety of different protocols. Cisco provides serial transition cables that automatically determine which protocol is being used.

The Smart Serial module requires a 26-pin connector on the interface card end. The network end of the cable depends on the protocol being used, as shown in Figure B-7.

Figure B-7: Serial Interface Adapter Cables

The exact cable required depends on the access router being used as the LAN gateway. If the access router, however, is a Cisco router using a Smart Serial or 60-pin LFH interface, the cables listed in Table B-1 can directly connect the serial interfaces.

Table B-1: Cables for Direct Serial Interface Connection when Using Cisco Routers

Cisco uBR910 Series Serial Interface (DCE) ¹ Cisco Access Router Serial Interface (DTE) Cable Part Number

Smart Serial, 26-pin connector

Smart Serial, 26-pin connector

CAB-SSC-SST-V35²

Smart Serial, 26-pin connector

LFH, 60-pin connector

CAB-SSC-5in1T-V35²

Smart Serial, 26-pin connector

EIA-530, DB-25 connector

CAB-SS-530FC

Smart Serial, 26-pin connector

X.21, DB-15 connector

CAB-SS-X21FC

Smart Serial, 26-pin connector

V.35, DB-37 connector

CAB-SS-V35FC

¹ When connecting the Smart Serial interface to a Smart Serial or LFH interface, the V.35 protocol is assumed because it provides the highest bandwidth and reliability.
² The Smart Serial cable can be used with any of the protocols supported on these serial interfaces.

Cisco uBR910 Series Serial Interface (DCE) ¹	Cisco Access Router Serial Interface (DTE)	Cable Part Number
Smart Serial, 26-pin connector	Smart Serial, 26-pin connector	CAB-SSC-SST-V35²
Smart Serial, 26-pin connector	LFH, 60-pin connector	CAB-SSC-5in1T-V35²
Smart Serial, 26-pin connector	EIA-530, DB-25 connector	CAB-SS-530FC
Smart Serial, 26-pin connector	X.21, DB-15 connector	CAB-SS-X21FC
Smart Serial, 26-pin connector	V.35, DB-37 connector	CAB-SS-V35FC

Note When using the cables shown in Table B-1, the Cisco uBR910 series DSU must be configured as the DCE device and the Cisco router (the access router) must be configured as the DTE device.

Smart Serial (DCE) to Smart Serial (DTE) Cable

Table B-2 shows the cabling required for the cable that connects the Smart Serial interface on the Cisco uBR910 series DSU (configured as a V.35 DCE) to an access router that is using the Smart Serial synchronous WAN interface module (configured as a V.35 DTE):

Table B-2: V.35 Smart Serial to Smart Serial V.35 Cable Diagram
DCE Pins Direction DTE Pins Signal Description (from DCE point of view)

1

--->

5

TXD/RXD+

Transmit Data+

2

--->

4

TXCE/RXC+

Transmit Clock External+

3

<---

3

TXC/TXC+

Transmit Clock+

4

<---

2

RXC/TXCE+

Receive Clock+

5

<---

1

RXD/TXD+

Receive Data+

6

<---

6

DCD/DCD+

Data Carrier Detect+

7

--->

12

DTR/DSR+

Data Terminal Ready+

8

--->

11

RTS/CTS+

Ready To Send+

11

<---

8

CTS/RTS+

Clear To Send+

12

<---

7

DSR/DTR+

Data Set Ready+

13

--->

13

LL/LL+

Local Loopback

14

--->

18

TXD/RXD-

Transmit Data-

15

--->

17

TXCE/RXC-

Transmit Clock External-

16

<---

16

TXC/TXC-

Transmit Clock-

17

<---

15

RXC/TXCE-

Receive Clock-

18

<---

14

RXD/TXD-

Receive Data-

19¹

---

19²

GND

Signal Ground

22¹
23
24

N/A

N/A

Mode 1
Mode 0
Mode DCE

Pins are connected locally on the DCE side to identify that this side of the cable is the DCE device.

N/A

N/A

22²
23

Mode 1
Mode 0

Pins are connected locally on the DTE side to identify that this side of the cable is the DTE device.

26¹

---

26²

GND

Signal Ground

Shield

---

Shield

Shield

Shield Ground

¹ Pins 19, 22, 23, 24, and 26 are connected together to Signal Ground on the DCE side of the cable.
² Pins 19, 22, 23, and 26 are connected together to Signal Ground on the DTE side of the cable.

**Table B-2: V.35 Smart Serial to Smart Serial V.35 Cable Diagram**
DCE Pins	Direction	DTE Pins	Signal	Description (from DCE point of view)
1	--->	5	TXD/RXD+	Transmit Data+
2	--->	4	TXCE/RXC+	Transmit Clock External+
3	<---	3	TXC/TXC+	Transmit Clock+
4	<---	2	RXC/TXCE+	Receive Clock+
5	<---	1	RXD/TXD+	Receive Data+
6	<---	6	DCD/DCD+	Data Carrier Detect+
7	--->	12	DTR/DSR+	Data Terminal Ready+
8	--->	11	RTS/CTS+	Ready To Send+
11	<---	8	CTS/RTS+	Clear To Send+
12	<---	7	DSR/DTR+	Data Set Ready+
13	--->	13	LL/LL+	Local Loopback
14	--->	18	TXD/RXD-	Transmit Data-
15	--->	17	TXCE/RXC-	Transmit Clock External-
16	<---	16	TXC/TXC-	Transmit Clock-
17	<---	15	RXC/TXCE-	Receive Clock-
18	<---	14	RXD/TXD-	Receive Data-
19¹	---	19²	GND	Signal Ground
22¹ 23 24	N/A	N/A	Mode 1 Mode 0 Mode DCE	Pins are connected locally on the DCE side to identify that this side of the cable is the DCE device.
N/A	N/A	22² 23	Mode 1 Mode 0	Pins are connected locally on the DTE side to identify that this side of the cable is the DTE device.
26¹	---	26²	GND	Signal Ground
Shield	---	Shield	Shield	Shield Ground

Smart Serial (DCE) to LFH (DTE) Cable

Table B-3 shows the cabling required for the cable that connects the Smart Serial interface on the Cisco uBR910 series DSU (configured as a V.35 DCE) to an access router that is using the LFH synchronous interface (configured as a V.35 DTE).

Table B-3: Smart Serial to LFH Cable Diagram
DCE Pins (26-pin) Direction DTE Pins (60-pin) Signal Description (from DCE point of view)

1

--->

28

TXD/RXD+

Transmit Data+

2

--->

26

TXCE/RXC+

Transmit Clock External+

3

<---

24

TXC/TXC+

Transmit Clock+

4

<---

20

RXC/TXCE+

Receive Clock+

5

<---

18

RXD/TXD+

Receive Data+

6

<---

33

DCD/DCD+

Data Carrier Detect+

7

--->

34

DTR/DSR+

Data Terminal Ready+

8

--->

35

RTS/CTS+

Ready To Send+

11

<---

42

CTS/RTS+

Clear To Send+

12

<---

43

DSR/DTR+

Data Set Ready+

13

--->

44

LL/LL+

Local Loopback

14

--->

27

TXD/RXD-

Transmit Data-

15

--->

25

TXCE/RXC-

Transmit Clock External-

16

<---

23

TXC/TXC-

Transmit Clock-

17

<---

19

RXC/TXCE-

Receive Clock-

18

<---

17

RXD/TXD-

Receive Data-

19¹

---

16

GND

Signal Ground

22¹
23

N/A

N/A

Mode 1
Mode 0

Pins are connected locally on the DCE side to identify that this side of the cable is the DCE device.

N/A

N/A

48
49

GND
Mode 1

Pins are connected locally in the indicated groups on the DTE side to identify that this side of the cable is the DTE device.

N/A

N/A

50
51
52

Mode 0
GND
Mode DCE

N/A

N/A

53
54
55
56

TXC/NIL
RXC/TXCE
RXD/TXD
GND

26¹

---

16

GND

Signal Ground

Shield

---

Shield

Shield

Shield Ground

¹ Pins 19, 22, 23, and 26 are connected together to Signal Ground on the DCE side of the cable.

**Table B-3: Smart Serial to LFH Cable Diagram**
DCE Pins (26-pin)	Direction	DTE Pins (60-pin)	Signal	Description (from DCE point of view)
1	--->	28	TXD/RXD+	Transmit Data+
2	--->	26	TXCE/RXC+	Transmit Clock External+
3	<---	24	TXC/TXC+	Transmit Clock+
4	<---	20	RXC/TXCE+	Receive Clock+
5	<---	18	RXD/TXD+	Receive Data+
6	<---	33	DCD/DCD+	Data Carrier Detect+
7	--->	34	DTR/DSR+	Data Terminal Ready+
8	--->	35	RTS/CTS+	Ready To Send+
11	<---	42	CTS/RTS+	Clear To Send+
12	<---	43	DSR/DTR+	Data Set Ready+
13	--->	44	LL/LL+	Local Loopback
14	--->	27	TXD/RXD-	Transmit Data-
15	--->	25	TXCE/RXC-	Transmit Clock External-
16	<---	23	TXC/TXC-	Transmit Clock-
17	<---	19	RXC/TXCE-	Receive Clock-
18	<---	17	RXD/TXD-	Receive Data-
19¹	---	16	GND	Signal Ground
22¹ 23	N/A	N/A	Mode 1 Mode 0	Pins are connected locally on the DCE side to identify that this side of the cable is the DCE device.
N/A	N/A	48 49	GND Mode 1	Pins are connected locally in the indicated groups on the DTE side to identify that this side of the cable is the DTE device.
N/A	N/A	50 51 52	Mode 0 GND Mode DCE
N/A	N/A	53 54 55 56	TXC/NIL RXC/TXCE RXD/TXD GND
26¹	---	16	GND	Signal Ground
Shield	---	Shield	Shield	Shield Ground

Console Port Connector and Cables

The Cisco uBR910 series DSU provides an RJ-45 serial connector for asynchronous serial console access. The console port is a DCE device, so connecting it to another DTE device, such as the serial port on a laptop PC, requires a straight-through DCE-to-DTE cable.

Table B-4 lists the pinouts for the console port and for the cabling required when connecting to a DTE device that uses an RJ-45, DB-25, or DB-9 connector.

Table B-4: Console Port Signaling and Cabling

Console Port (DCE) Terminal Port (DTE)

Signal RJ-45 Pinout RJ-45 Pinout DB-25 Pinout DB-9
Pinout Signal

RTS

1¹

8

5

8

CTS

DTR

2

7

6

6

DSR

TxD

3

6

3

2

RxD

GND

4

5

7

5

GND

GND

5

4

7

5

GND

RxD

6

3

2

3

TxD

DSR

7

2

20

4

DTR

CTS

8¹

1

4

7

RTS

¹ The console port does not support hardware flow control, so it does not use or support the RTS and CTS signals. To accommodate other devices that use these signals, pin 1 on the console port (RTS) is connected internally to pin 8 (CTS), so that devices that assert the RTS signal automatically receive the CTS signal in reply.

Console Port (DCE)
Signal	RJ-45 Pinout	RJ-45 Pinout	DB-25 Pinout	DB-9 Pinout	Signal
RTS	1¹	8	5	8	CTS
DTR	2	7	6	6	DSR
TxD	3	6	3	2	RxD
GND	4	5	7	5	GND
GND	5	4	7	5	GND
RxD	6	3	2	3	TxD
DSR	7	2	20	4	DTR
CTS	8¹	1	4	7	RTS

The console port is hardwired for 9600 baud, 8 data bits, no parity, 1 stop bit (9600 8N1) and does not support either hardware or software flow control. If the console port is connected to a laptop computer or other PC when the Cisco uBR910 series is first powered-on, the initial system banner should be displayed on the computer's console screen. If you do not see the system banner, verify that the laptop's serial port is set correctly and that it is properly connected to the console port.

Note By default, downloading a Cisco IOS configuration file disables the console port and erases all previously saved configurations. The Cisco uBR910 series DSU ships from the factory with the console port enabled, and it remains enabled from the time of initial power-on until it begins to download a Cisco IOS configuration file. To change this default behavior so that the console port remains enabled, see the Cisco uBR910 Series Software Configuration Guide.

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Connector and Cable Specifications