ASM-20Installation and Operation Manual

Appendix B. IR-G.703 Codirectional Interface (64 kbps)

 

 

This mode corresponds to the modem clock working in the EXT mode.

Modem A

Modem B

 

IR -G .7 03 M odu le

 

 

 

 

T X D a ta

D a ta

 

T X

R X

 

C lo ck

 

 

C L K

 

 

 

G .7 03

R e cove ry

 

 

 

C lo ck

 

 

 

 

C o d ire ctio nal

F IF O

 

 

 

O u t

 

 

 

6 4 kbp s n etw ork

 

 

 

C lo ck

 

D a ta

 

 

 

 

 

 

R e cove ry

 

 

 

 

 

 

R X D a ta

 

C lo ck

R X

T X

Tim in g S ou rce

 

R e cove ry

 

 

 

 

 

C lo ck In

 

 

 

 

F IF O

 

 

 

 

 

 

 

 

 

E X T C lock M od e

 

 

R C V C lock M od e

Figure B-3 IR-G.703 EXT Mode Timing Block

B.4 INT/RCV Mode

This mode is used in applications where the G.703 codirectional 64 kbps equipment connected to the modem recovers the clock signal from the modem link. This mode is used mainly when the attached equipment has a G.703 codirectional interface, but is not able to produce clock signals. The module has a 8-bit FIFO buffer to compensate for the phase delay introduced by the G.703 device. Figure B-4illustrates the buffer connection and the required application setup.

This mode corresponds to the modem clock working in the INT or RCV mode.

INT or RCV Clock M ode

DTE

side

M odem A

 

 

M odem B

 

 

LINK

 

 

G .703

 

side

 

 

side

 

 

 

 

IR -G .703 M odule

 

 

TX

R X

Clock

Data

RX Data

 

 

 

 

 

CLK

 

EXT, INT or RCV

 

 

Recovery

 

 

 

Clock

 

 

Clock M ode

 

 

 

 

 

 

O ut

FIFO

 

(Depending on the

 

 

TX Data

RX

TX

 

Data

attached network)

 

 

 

 

 

 

 

Clock

 

 

 

 

 

Recovery

 

 

 

 

FIFO

Clock In

 

 

 

 

INT/RCV Clock M ode

 

Equipment with G .703 interface

Figure B-4 IR-G.703 INT/RCV Mode Timing Block

INT/RCV Mode

B-3

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RAD Data comm ASM-20 operation manual INT/RCV Mode, Modem B, Odem a Odem B