9 V.120 ISDN Communications
This chapter describes how to
| 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 |
|
|
|
| |
Bundle | No | Yes | Yes |
Max. Line | Async: 38.4 | 64Kbps | 64Kbps |
Speed | Kbps | 128Kbps | 128Kbps |
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
V.120 ISDN Communications 57