B<value>—Communication Standard Setting

Use this command to select the communication standard used by the soft modem.

Result codes:

_ OK if <value> = 0—3, 15, 16.

_ ERROR if <value> 0—3, 15, 16.

Command

B0

B1

B2

B3

B15

B16

Function

Selects CCITT V.22 mode when the modem is at 1200 bits/s.

Selects Bell 212A when the modem is at 1200 bits/s (default).

Deselects V.23 reverse channel (same as B3).

Deselects V.23 reverse channel (same as B2).

Selects V.21 when the modem is at 300 bits/s.

Selects Bell 103J when the modem is at 300 bits/s (default).

C<value>—Carrier Control

This command is supported to ensure compatibility with communications software that issues the C1 command.

However, this modem does not support the C0 command. The C0 command instructs some modems not to send carrier (i.e., it puts them in receive-only mode).

Result codes:

_ OK if <value> = 1.

_ ERROR if <value> 1.

Command

C1

Function

Normal transmit carrier switching (default).

D<dial string>—Dial

This command instructs the soft modem to go off-hook and begin the dialing sequence. The dial string (<dial string>, including modifiers and the telephone number) is entered after the D command.

A dial string can be up to sixty characters long. Any digit or symbol may be dialed as touchtone digits. Characters such as spaces, hyphens, and parentheses are ignored by the modem and may be included in the dial string to enhance readability.

I<value>—Request ID Information

Use this command to display product information about the modem. In each case the information is transmitted to the host system followed by a final result code.

Result codes:

_As described in Table 8 if <value> = 0—9, 11.

_ERROR if <value> 0—9, 11.

I<value>—Request ID Information

Use this command to display product information about the modem. In each case the information is transmitted to the host system followed by a final result code.

Result codes:

_As described in Table 8 if <value> = 0—9, 11.

_ERROR if <value> 0—9, 11.

Command

L0

L1

L2

L3

Function

Low volume.

Low volume.

Medium volume (default).

High volume.

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Nortel Networks 56K manual Bvalue-Communication Standard Setting, Cvalue-Carrier Control, Ddial string-Dial
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56K specifications

Nortel Networks, a leading telecommunications equipment manufacturer, played a crucial role in the development of modem technology during the late 1990s and early 2000s. Among its most notable contributions was the Nortel Networks 56K modem. Introduced at a time when dial-up internet access was the norm, the 56K modem represented a significant leap forward in data transmission speeds for both residential users and businesses alike.

One of the main features of the Nortel Networks 56K modem was its ability to achieve faster data rates compared to its predecessors. While earlier modems operated at speeds of 28.8 Kbps or 33.6 Kbps, the Nortel 56K modem could theoretically reach connection speeds of 56 Kbps under optimal conditions. This enhancement was made possible through the implementation of newer modulation techniques, such as Pulse Amplitude Modulation (PAM), which allowed for more efficient data transmission over standard telephone lines.

The 56K modem was designed to work effectively over existing analog phone lines, which was a crucial characteristic during that time. It could connect directly to the existing Public Switched Telephone Network (PSTN), making it accessible for millions of users without the need for any special infrastructure upgrades. This meant that both home users and businesses could benefit from the increased speed without significant investment.

Another notable feature was the robustness of the Nortel 56K modem's error correction capabilities. Technologies such as V.42 and V.42bis compression were integrated to enhance data integrity. These error-correcting protocols stitched together fragmented data packets, thereby ensuring reliable and stable connections, even over less-than-perfect phone lines. This reliability was vital for users who relied on modems for email, file transfers, and browsing the web.

In terms of compatibility, the Nortel Networks 56K modem was designed to work seamlessly with various operating systems, ensuring that users could connect to the internet regardless of their hardware setup. The plug-and-play capability made installation straightforward, allowing users to start browsing the web quickly.

While the Nortel Networks 56K modem was eventually eclipsed by DSL and broadband technologies that offered even higher speeds, it played an instrumental role in transitioning users from slower modems to a more connected world. The impact of Nortel's 56K modem can still be felt today, as it laid the groundwork for future innovations in digital communications and paved the way for the fast-paced internet landscape we experience now.
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