SECTION 4D - HAYES COMPATIBLE MODEM INTERFACE
AT Command Summary
The following information is provided as a reference and is not necessarily
a complete description of the AT command set.
AT
AT command(s) follow
A
answer an incoming call and attempt to establish a connection
А/
repeat previous command string (do not follow with <CR>)
В
signal protocol selection
BO
CCITT V.22
B1
Bell 212A
&C
c a rrier detect signal
&C0
car r i e r detect signal active always
&C1
c a rrier detect signal follows car r i e r
&D
DTR m o n i t o r i n g
&D0
m o d e m ignores DTR
&D1
m o d e m m o n i t o r s for DTR
D
dial command
E
echo received commands control
EO
c o m mands are not echoed
El
c o mmands are e c hoed
H
hook (telephone line state)
HO
on hook
HI
off hook
I
modem status inquiry
10
d i s p l a y ID
11
d i s p l a y rom c h k s u m
L
speaker volume
L0
low
LI
low
L2
m e d i urn
L3
high
M
speaker control
MO
off always
Ml
on until connect
М2
on always
М3
on except when d i aling or when c a r r i e r dete c t e d
0
returns to online state after an escape while connected
00
r e - e s t a b l i s h onli n e state
01
r e - e s t a b l i s h onl i n e state but re-ad j u s t for phone
phone line con d i t i o n s (2400 baud only)
P
pulse dialing enabled
Q
quiet mode, controls sending responses to received commands
Q0
c o m m a n d responses are displ a y e d
Q1
com m a n d responses are not d i s p l a y e d
S
read or write to the S-Registers
Sr?
read value stored in register r
Sr=n
assign value n to register r
T
tone dialing enabled
V
response format
VO
respond wit h numeric codes
VI
respond wit h verbal codes
X
response convention
xo
m i n i m u m responses used (don't use w i t h Model 16)
XI
m i n i m u m r e sponses plus t r a n s m i s s i o n speed identifier
X2
same as XI but waits for dial ton e before dia l i n g
X3
same as XI but BUSY, N0 ANSWER, and tone detec t i o n
m e s s a g e s are also displ a y e d
X4
same as X3 but waits for dial tone b e fore d i a ling
Y
long space disconnect
Y0
d i s a b l e d
Y1
tra n s m i t s 4 seconds of space befo r e discon n e c t
Z
reset modem
4D-7
