Chapter 4 - AT Commands, S-Registers, and Result Codes

S-Register:

S53

Function:

Maximum X.75 Buffer Size

Unit:

1 byte

Range:

n=64 - 2048

Default:

2048 (bytes)

Description: S53 allows the maximum buffer size of an X.75 frame to be customized.

 

Typically a smaller frame size is more compatible with software packages on

 

a PC (such as HyperTerminal). Larger frame sizes introduce larger delay

 

which some software cannot deal with appropriately.

S-register:

S54

Function:

Force 56 Kbps B-Channel Data Rate

Unit:

Decimal ASCII code

Range:

n=56 (Kbps) or 64 (Kbps)

Default:

64 (Kbps)

Description: S54 can be used to force a 56 Kbps B-channel data rate in order to make 56 Kbps data

 

calls.

S-Register:

S55

Function:

POTS Port Call Control

Unit:

Decimal ASCII code

Range:

1, 2, 17, 18

Default:

1

Description: Allows you to set the type of information transfer capability for calls placed from the

 

POTS port either by a telephone, modem, or fax. Some Central Office (CO) switches

 

keep track of the type of line each customer has, and if that line is labeled as a data line

 

(modem or fax), it will not accept a speech call originated on that line. However, 3.1 kHz

 

audio information transfer capability is allowed on data lines (modem or fax) by most

 

switches. S55 also lets you define whether a progress indicator information element

 

(which indicates that the origination address of the POTS call is non-ISDN) is sent with

 

the SETUP message for the POTS port call. This may help POTS port calls get through

 

certain CO switches.

 

S1

Speech, no progress indicator

 

S2

3.1 kHz Audio, no progress indicator

 

S17

Speech, origination address is non-ISDN

 

S18

3.1 kHz Audio, origination address is non-ISDN

S-register:

S56 (applies to NET3 [!C0=2] switch type only)

Function:

Calling Party Number IE Settings

Unit:

decimal ASCII code

Range:

128

Disable

 

Type of Number

 

0

Unknown,

 

16

International

 

32

National

 

48

Network specific

 

64

Subscriber

 

96

Abbreviated

69