Northern UTA220/UTA220k - Manual (Page 71)

UTA220/UTA220k
9-3
Rate Adaption
V.120
V.120 is a CCITT protocol that supports synchronous and
asynchronous rate adaption, and also provides link-layer error
control. Although errors on a digital network are rarer than on
an analog telephone line, they are possible. V.120 provides an
end-to-end protocol for detecting and correcting any such
errors. V.120 also performs buffering and can thus support
flow control to and from the DTE.
To select V.120 with the LCD, scroll through the menu and
select:
• CONFIGURATION OPTIONS?
• PORT CONFIG OPTIONS?
• PROTOCOL OPTIONS?
• PROTOCOL = V.120
To select V.120 with the AT%A2 command, enter AT%A2=2.
V.120 Options
Maximum Transmit Frame Size is the maximum size a frame
can be for transmitting. The transmit frame size affects the
store-and-forward delay.
Maximum Receive Frame Size is the maximum size frame that
is accepted by the TA. Larger frames are rejected.
Window Size is the number of frames that can be sent before
an acknowledgment is received. This parameter is normally
not changed.
T200 Timer is the length of time to wait for acknowledgment
of a sent frame. If this timer expires, V.120 attempts to send
the frame again.