X21 DCE Pinout

Sir I am B.Tech student and doing the enginnering in the Electronics engineering so can I want to know about the X21 DCE Pinout so can you please tell me the same

[Pathak]

Hey buddy The X.21 interface was recommended by the CCITT in 1976.

It is defined as a digital signaling interface between customers (DTE) equipment and carrier's equipment (DCE).


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

Info is in the below format

60 Pin1 Signal

Description

Direction

15 Pin Signal




X.21 is a state-driven protocol running full duplex at 9600 bps to 64 Kbps with subscriber networks.

It is a circuit-switching protocol using Synchronous ASCII with odd parity to connect and disconnect a subscriber to the public-switching network.

X.21 provides eight signals:

Signal Ground (G) -

DTE Common Return (Ga) -

Transmit (T) -

Receive (R) -

Indication (I) -

Signal Element Timing (S) -

Byte Timing (B) -

Electrical Characteristics.

Data signaling rates of 9600 bit/s and below. X.27 (= V. 11) & X.26 (= V. 10)

Data signaling rates above 9600 bps. X.27 (= V. 11)

[V.10 specifies an interface circuit with an unbalanced transmitter with a differential
receiver.]

[V.11 specifies an interface circuit with a differential, balanced signal from transmitter to
receiver which may accommodate an optional DC offset voltage. This approximates EIA-
4221

X.21 Speed and Distance Limitations