2 at commands, 1 a – answer, A/ – repeat last command – Maxim Integrated 73M2901CE AT Command User Manual

Page 8: B – bell, itu, v.23, or bell202 operation, 4 c[n] – select carrier detect option, At commands, A – answer, C[n] – select carrier detect option

73M2901CE AT Command User Guide

UG_2901CE_027

Rev.

2.0

Return to Data Mode

Issue the following command:

ATO

The modem should respond with:

CONNECT [DTE SPEED]

The modem is now back in data mode and ready to send and receive data.

2 AT Commands

2.1

A – Answer

The A command causes the modem to immediately go on-line (off-hook) in the Answer mode and attempt
to handshake regardless of the value of register S0, discussed later. This command gives you a method
of manually answering an incoming phone call. For restrictions, see also the R command.

2.2

A/ – Repeat Last Command

The A/ command causes the modem to re-execute the last command that was issued. For example, this
command can be used to redial a number if the previous command was a dial command.

NOTE: A/ and +++ are the only commands that are neither preceded by AT nor followed by .

2.3

B – Bell, ITU, V.23, or Bell202 Operation

The B[n] command is used to select between modes of operation.

B0

Selects ITU V.22Bis, V.22 or V.21 operation (default).

Selects Bell212A or Bell103 operation.

Selects 1200 bps. receive and 75 bps. transmit for V.23 operation.

Selects 75 bps. receive and 1200 bps. transmit for V.23 operation.

Selects 1200 bps. receive for Bell202 operation.

Selects 1200 bps. transmit for Bell202 operation.

Selects 1200 bps. receive and transmit for 4-Wire V.23 operation. (V23T)

Selects 1200 bps. receive and transmit for 4-Wire Bell202 operation. (B202T)

B10 Selects 1200 bps V.23 Half duplex mode ( V23H). B10 and B11 are the same.
B11 Selects 1200 bps V.23 Half duplex mode ( V23H). B10 and B11 are the same.

2.4

C[n] – Select Carrier Detect Option

The C[n] command selects how the Carrier Detect (CD) signal is controlled.

C0

CD forced ON. (Default)

CD ON in presence of valid debounced carrier signal.

CD ON in presence of raw carrier signal. Receive data independent of valid carrier signal. (May
be reserved)

Operation of DCD:
Normal modes:

C0 – ON at all times