ITU-V25 Bis and Hayes

V25Bis/Hayes structure: fields

Reference standard: CCITT Recommendation V25 bis.

Asynchronous:

length field or string
OFF
n characters Command message
1 character CR
1 character LF

Synchronous:

length ield or string
2 octets SYN-SYN
1 octet STX
n octets Command message
1 octet ETX

HDLC:

bits 1 _ _ _ _ _ _ 8 ield or string
Opening FLAG
1 octet Address= 11111111 =FF H
1 octet Control= 00010011 or 00000011.
UI frame = 13 H or 03 H
n octets Command message
2 octets FCS

V25Bis format: command

Command designation Parameters
CRN C Call Request Number Number to be dialed xxxxx
CRI C Call Request Identification Number to be dialed + Identif.
xxxxx:yyyy
CRS C Call Request Address Memory address mmm
PRN C Program Number Memory address + Number
mmm : xxxxx
PRI C Program Identification Identification yyyyyy
RLN C List Request stored Number
RLF C List Request forbidden Number
RLF C List Request delayed call numbers
RLI C List Request identification numbers
DIC C Disregard Incoming Call
CIC C Connect Incoming Call
CFI I Call Failure Indication Failure type xx
DLC I Delayed Call Time duration tttttttt
INC I Delayed Call
VAL I Valid
INV I Invalid
LSN I List stored number Memory address + Number
mmm : xxxxx
LSF I List forbidden Number Memory address + Number
mmm : xxxxx
LSD I List delayed Number Memory address + Number
mmm : xxxxx
LSI I List ident. Number Identification yyyyyy

V25Bis Number format

Alphabet
0-9 Dialing Digit
: Wait tone
< Pause
= Separator
P Dialing to be continue in Pulse mode
T Dialing to be continue in DTMF

 

Hayes format: command

Command designation
AT Command Prefix

Indication designation
OK Command done
ERROR Command error
CONNECT Connection

Command designation Parameters
A Manual answer
A/ Repeat last command
D Dial Number to be dialed
M0 Speaker off
M2 Speaker always on
L0 Speaker volume Low
L3 Speaker volume High
Sr? Read value register r (decimal)
Sr=v Set value v in register r
&F Restore Factory configuration
&V View configuration Profile
V0 Status code results=numbers
V1 Status code results=messages
&W Store current configuration

Hayes Number format

Alphabet
0-9
#ABCD		 Dialing Digit
W Wait tone
, Pause
P Dialing to be continue in Pulse mode
T Dialing to be continue in DTMF

 

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updated:  27-Feb-04