![background image](/i/zyxel/147524/zyxel-omni-ta128/h/zyxel-omni-ta128-063.png)
51
8
V.120 ISDN
Communications
This chapter describes how to set-up and configure your TA128
with the V.120 ISDN protocol. The table below shows the
specifications of different ISDN protocols:
V.110
V.120
X.75
Layer 1
80 Bits
Framing
HDLC
HDLC
Layer 2
None
LAPD
LAPB
Transparent
Layer 3
None
V.120
ISO8208T.70 NL
Error Control
No
Yes
Yes
V.42bis
No
Yes
Yes
Async or Sync
if used with V-
Series DTE
Async Only
Async
Only
Async Only
Bundle
No
Yes
Yes
Max. Line
Speed
Async: 38.4
Kbps
64Kbps
128Kbps
64Kbps
128Kbps
AT-Command
Configuration
ATB10
ATB20
ATB00
Transparent
ATB01: T.70 NL
Placing outgoing calls
Some switches transmit all network signals through the D channel
(out of band signaling), allowing both B channels to be used
exclusively for your communication purposes. This allows for
throughput of 64Kbps per channel. However, not all switches
support out-of-band signaling at this time. For switches that do not