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Serial Pinout Diagrams

 
V.35 Pinouts

General
V.35 is a partially balanced, partially single-ended interface specification. The data leads and clock leads are balanced, the handshake leads are single-ended. Most commonly used for 56kbps and 64kbps data rates.

 

DATA LEADS

CONTROL LEADS

Vdc

B > A

A > B

-3 to -25

+3 to +25

binary

1

0

1

0

signal

MARK

SPACE

MARK

SPACE

function

off

on

off

on

 

Transmitter output voltage from a balanced tranmitter indicating a MARK is +0.35Vdc for the B line, -0.2Vdc for the A line. Indication of a SPACE condition is +0.35Vdc for the A line, -0.2Vdc for the B line. Output voltage difference is 0.55Vdc. To make sense to the receiver it must be at least 0.01Vdc difference between the A line and B line. Maximum cable length depends on required speed and cable capacitance. The extremes specified are 2000ft/600m to 4000ft/1200m @ 100kbps, 300ft/90m at 10Mbps. Sync applications only, no async V.35 equipment around.

More speed/distance equations: 610m @ 64 kbps.

Pinning

M/34 Male

M/34 Female

M/34 Male

M/34 Female

 

Pin

Signal

Abbr.

DTE

DCE

A

Chassis Ground

 

-

-

B

Signal Ground

 

-

-

C

Request To Send

RTS

Out

In

D

Clear To Send

CTS

In

Out

E

Data Set Ready

DSR

In

Out

F

Data Carrier Detect

DCD

In

Out

H

Data Terminal Ready

DTR

Out

In

J

Local Loopback

LL

In

Out

K

Local Test

 

Out

In

L

Unassigned

M

Unassigned

N

Unassigned

P

Send Data A

TxD-

Out

In

R

Receive Data A

RxD-

In

Out

S

Send Data B

TxD+

Out

In

T

Receive Data B

RxD+

In

Out

U

Terminal Timing A

 

Out

In

V

Receive Timing A

 

In

Out

W

Terminal Timing B

 

Out

In

X

Receive Timing B

 

In

Out

Y

Send Timing A

 

In

Out

Z

Unassigned

AA

Send Timing B

 

In

Out

BB

Unassigned

CC

Unassigned

DD

Unassigned

EE

Unassigned

FF

Unassigned

HH

Unassigned

JJ

Unassigned

KK

Unassigned

LL

Unassigned

MM

Unassigned

NN

Unassigned

 

Special Notes
There seem to be two versions of the V.35 pinning. One is called V.35 Winchester, the other is called V.35 Straight. One is mirrored to the other. We don't know how it is mirrored. This information came from a 3Com source. Their Access Builder 4000 V.35 Card interface is V.35 Straight they say. The Dutch PTT supplies V.35 interface according to V.35 Winchester. Connecting these two requires some sort of crossed cable. Crossed pinning presently unknown. If someone has more information please let us know!

There are two versions of V.35 screw locks. The US-version measures 16/10 mm (the large one), the French version measures 10/10 mm (the small one). The US-version is also known as Domestic and the French version is also called International.

A

-

A

B

-

B

C

-

F

F

-

C

E

-

H

H

-

E

R

-

P

T

-

S

P

-

R

S

-

T

V

-

U

X

-

W

U

-

V

W

-

X