9 V.120 ISDN Communications

This chapter describes how to set-up and configure your TA 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

HDLC

HDLC

 

Framing

 

 

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

Async Only

Async

Async Only

if used with

 

Only

 

V-Series DTE

 

 

 

Bundle

No

Yes

Yes

Max. Line

Async: 38.4

64Kbps

64Kbps

Speed

Kbps

128Kbps

128Kbps

AT-Command

ATB10

ATB20

ATB00

Configuration

 

 

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

V.120 ISDN Communications 57

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ZyXEL Communications omni series user manual Isdn Communications, Placing outgoing calls