Section 13: X.21
T
ieline
T E C H N O L O G Y
Page 93
Figure 25: X.21 ISDN Interface Connection
13.3.
Connecting Via X.21
First install the X.21 module into your codec. The connection should then appear
in the root menu of the main codec
LCD
screen. For the procedure to connect
over X.21, please see the Quick Start section of this reference manual. This will
display the menu wizard for X.21 module connections and explain the Quick
Start connection procedure to get you connected.
13.3.1.
X.21 over Leased Lines
With C/DTR call establishment, a ‘C’ (Control Signal) is used to enable and
disable call control protocols. An ‘I Signal’ (incoming call signal) is used to
indicate the presence of an incoming call.
When dialing from one codec to another, the dialing codec (DTE1) changes
the C Signal from off to on to initiate an outbound call. At the codec (DTE2)
receiving the call an ‘I Signal’ (‘Indication’ or incoming call signal) changes
from off to on, indicating the presence of an incoming call. The codec
receiving the call then initiates a C Signal state change, from off to on, and
replies to the dialing codec, which receives the incoming signal and changes
its I Signal state from off to on. This completes the call connection process
over X.21.
To clear a call, press
HANG UP
on either codec to change the C Signal from
on to off. This will terminate the connection between the codecs.
For more information on how to connect via X.21 using
T
ieline
codecs,
please see the X.21 or Quick Start section of this reference manual or contact
customer support at [email protected] for more info.
