4 1 1 Enabling Legacy P TP Cameras a n d Printers as Networked PT P I Appliances Petronel Bigioi, Illariu Raducan, Eran Steinberg, a n d Peter Corcoran, Member, IEEE Abstract PTP/IP i s a ne w connectivity standard f o r networkedimaging appliances which combines the ease ofuse a n d seamless connectivity o f Picture Transfer Protocol (PTP) with th e ubiquity of TCP/IP networks. I n this paper we examine methods t o allow legacy P T P appliances t o gain t h e benefits o f PTP/IP through th e design of bridge a n d gateway adapters which can be simply plugged into t h e U S B ports o f such appliances. The internal firmware stacks of such adapters a r e described an d practical case studies describe the adaption o f legacy PTP cameras a n d printers t o connect over a conventional 802.11 wireless LAN Keywords Digial Cameras, Network Transport Protocols, Picture Transfer Protocol, Device Connectivity a n d Consumer Electronics. I . INTRODUCTION With the wide adoption o f ne w wireless technologies i t w a s clear that sooner o r latter t h e digital still camera will become a networking device. A ne w transport protocol, PTP/IP wa s adopted a s a CIPA standard i n 2005 [3]. T h e ne w transport i s described i n detail i n [ 4 ] a nd i t enables PT P [1], which could previously only b e used with U S B device connections [2], t o b e used with TCP/IP networks. Th e PTP/IP standard allows extension to a network environment without affecting applications that us e PTP. I t also enables multiple simultaneous connections among digital imaging devices, which w a s n o t possible with PT P over USB. With PT P [5-7], digital cameras c a n exchange images with host computers, printers, other imaging a n d display devices. T h interoperability resulting from t h e widespread adoption o f PT P over U S B transport h a s greatly reduces consumers' frustration a t t h e difficulty o f transferring photos from camera t o computer, printer, o r kiosk, a nd contributed t o t h e ongoing growth i n sales o f digital cameras a nd associated devices. While PTP/IP enables next generation products t o function over 802.11 home WLANs there remains large installed base o f legacy PT P appliances. With t he vent o f PTP/IP t h e users o f such cameras a nd printers m ay feel unhappy that these recently purchased products already obsolete a n d m ay b e reluctant t o p a y t h e cost o f upgrading to a ne w PTP/IP compatible printer or camera. I n turn this m ay slow t h e adoption o f PTP/IP i n t h e market. Bearing these factors i n mind a decision wa s taken t o Petronel Bigioi i s V P o f Engineering a t FotoNation (Ireland) Ltd.; e - mail: petronelAfotonation.com. Illariu Raducan is a Senior Engineer at FotoNation (Ireland) Ltd.; e - mail: laleAfotonation.com. Peter Corcoran i s with t h e Faculty o f Engineering a t National Univeristy o f Ireland, Galway; e-mail: peter.corcoranAnuigalway.ie. Eran Steinberg is C E O o f FotoNation Inc.; e-mail: erans fotonation. com. investigate t h e feasibility o f creating low-cost U S B adapters with 802.11 connectivity which could convert legacy cameras a n d printers into PTP/IP compatible appliances. This would allow existing users o f PT P products a low-cost upgrade t o convert these legacy appliances n d gain t he benefits o f full device connectivity over a home WLAN A s generic l ow cost U S B t o WLAN adapters a r e available t h e k e y design problems relate t o the additional adaption which i s required t o the internal firmware stacks o f these adapters i n order t o support t h e additional signaling requirements o f PTP/IP i n particular t h e requirements f o r device discovery n d device bonding which a re inherent i n PTP/IP. I I SYSTEM DESIGN A number o f alternative WLAN chipsets a nd S o C hardware platforms were investigated. Each o f these h a d various pros a n d cons a n d a brief summary o f o u r initial feasibility studies for several such platforms i s given. I t wa s found that hardware platforms where there i s support fo r open source software tend t o b e easier t o work with a n d k e y adaptations o f t h e firmware to th e underlying hardware tend to more easily achieved. Initial prototyping w a s achieved using a commodity wireless access point t o which a full open-source operating system ha d been ported. This providedcomplete hardware level access to a mass market chipset f o r negligible set-up costs andwas a k e y factor i n completing t h e initial product feasibility studies. Some firmware modifications were required i n the adapter firmware over and above the normal adaption o f a U S B stack t o provide TCP/IP connectivity. These included: A . Device Discovery Mechanism A specialized PTP-IP discovery protocol w a s developed fo r this purpose a nd serves a role t o that o f other service a n d device discovery protocols: i t helps t o find devices a n d services i n t h e networking environments. I t s targeted scope, however, is limited to discovering imaging devices that support PTP-IP. This discovery protocol c a n be used instead o f standard protocols like UPnP a n d Rendezvous when t h e complexity o f the standard approaches i s beyond t h e capabilities o f many imaging appliances. T h e protocol i s based o n U D P broadcast mechanisms a n d c an b e used i n conjunction with TCP/IP stacks that d o no t implement multicasting. B.Device Bonding Mechanisms Dynamic Bonding. this approach c an b e implemented o n devices with more sophisticated user interfaces a n d i t i s built o n thefeature o f PTP-IP protocol where the exchange o f GUIDs between devices occurs during t h e PTP/IP connection establishment phase. T h e implementation f 1-4244-0763-X/07/ 20.00 ©2007 IEEE
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
8/10/2019 04146055
http://slidepdf.com/reader/full/04146055 1/2
4 1
1
Enabling Legacy
PTP
Cameras and
P r i n t e r s as
Networked
PTP IP
Appliances
P e t r o n e l B i g i o i ,
I l l a r i u R a d u c a n ,
E r a n
S t e i n b e r g , a n d
P e t e r C o r c o r a n ,
M e m b e r , IEEE
A b s t r a c t
P T P / I P
i s
a
ne w
c o n n e c t i v i t y
s t a n d a r d
f o r
n e t w o r k e d i m a g i n g a p p l i a n c e s w h i c h c o m b i n e s t he e as e o f u s e
a n d
s e a m l e s s
c o n n e c t i v i t y
o f P i c t u r e T r a n s f e r P r o t o c o l
( P T P )
w i t h
t h e
u b i q ui t y o f T C P / I P n e t w o r k s . I n t h i s p a p e r we
e x a m i n e
m e t h o d s t o a l l o w
l e g a c y
PTP a p p l i a n c e s t o g a i n
t h e
b e n e f i t s o f
P T P / I P t h r o u g h
t h e d e s i g n o f
b r i d g e a n d g a t e w a y
a d a p t e r s w h i c h c a n b e s i mp l y p l u g g e d
i n t o
t h e USB
p o r t s
o f
s u c h
a p p l i a n c e s . Th e i n t e r n a l
f i r m w a r e
s t a c k s
o f s u c h
a d a p t e r s
a r e d e s c r i b e d a n d
p r a c t i c a l
c a s e s t u d i e s
d e s c r i b e t h e
a d a p t i o n o f l e g a c y
PTP c a m e r a s
a n d p r i n t e r s t o
c o n n e c t
o v e r
a
c o n v e n t i o n a l 8 0 2 .1 1
w i r e l e s s LAN
K e y w o r d s
D i g i a l C a m e r a s , N e t w o r k T r a n s p o r t
P r o t o c o l s ,
P i c t u r e
T r a n s f e r
P r o t o c o l ,
D e v i c e
C o n n e c t i v i t y
a n d
C o n s u m e r
E l e c t r o n i c s .
I . I N T R O D U C T I O N
W i t h
t h e
w i d e
a d o p t i o n
o f new w i r e l e s s t e c h n o l o g i e s
i t
w a s c l e a r t h a t
s o o n e r
o r l a t t e r t h e
d i g i t a l s t i l l c a m e r a
w i l l
b e c o m e a
n e t w o r k i n g
d e v i c e .
A
new t r a n s p o r t
p r o t o c o l ,
P T P / I P
w a s
a d o p t e d
a s
a CIPA s t a n d a r d
i n
2 0 0 5
[ 3 ] .
T h e
new
t r a n s p o r t
i s
d e s c r i b e d
i n d e t a i l i n
[ 4 ] a n d
i t
e n a b l e s
PTP [ 1 ] , w h i c h c o u l d
p r e v i o u s l y
o n l y
b e
u s e d w i t h USB
d e v i c e c o n n e c t i o n s [ 2 ] , t o b e
u s e d
w i t h T C P / I P n e t w o r k s .
T h e P T P / I P s t a n d a r d a l l o w s e x t e n s i o n
t o a
n e t w o r k
e n v i r o n m e n t w i t h o u t
a f f e c t i n g a p p l i c a t i o n s
t h a t u s e P T P . I t
a l s o
e n a b l e s m u l t i p l e
s i m u l t a n e o u s
c o n n e c t i o n s
a m o n g
d i g i t a l i m a g i n g d e v i c e s ,
w h i c h
w a s n o t
p o s s i b l e
w i t h PTP
o v e r
U S B .
W i t h
PTP
[ 5 - 7 ] , d i g i t a l
c a m e r a s
c a n
e x c h a n g e i m a g e s
w i t h
h o s t
c o m p u t e r s , p r i n t e r s ,
o t h e r
i m a g i n g
a n d
d i s p l a y
d e v i c e s . T h e
i n t e r o p e r a b i l i t y r e s u l t i n g
f r o m
t h e
w i d e s p r e a d
a d o p t i o n
o f
PTP
o v e r
USB t r a n s p o r t
h a s
g r e a t l y
r e d u c e s
c o n s u m e r s ' f r u s t r a t i o n
a t t h e
d i f f i c u l t y
o f
t r a n s f e r r i n g
p h o t o s f r o m
c a m e r a t o c o m p u t e r , p r i n t e r , o r k i o s k , a n d
c o n t r i b u t e d t o t h e
o n g o i n g g r o wt h
i n
s a l e s
o f
d i g i t a l
c a m e r a s
a n d a s s o c i a t e d
d e v i c e s .
W h i l e
P T P / I P
e n a b l e s
n e x t
g e n e r a t i o n p r o d u c t s
t o
f u n c t i o n
o v e r 8 0 2 . 1 1
h o m e
WLANs
t h e r e
r e m a i n s
a
l a r g e
i n s t a l l e d b a s e o f l e g a c y
PTP
a p p l i a n c e s .
W i t h
t h e v e n t
o f
P T P / I P
t h e u s e r s
o f
s u c h c a m e r a s
a n d
p r i n t e r s may
f e e l
u n h a p p y
t h a t t h e s e
r e c e n t l y p u r c h a s e d p r o d u c t s
a r e
a l r e a d y
o b s o l e t e a n d
may
b e r e l u c t a n t t o
p a y
t h e c o s t
o f
u p g r a d i n g
t o a
ne w
P T P / I P c o m p a t i b l e p r i n t e r
o r
c a m e r a .
I n
t u r n t h i s
may
s l o w t h e
a d o p t i o n
o f
P T P / I P
i n
t h e m a r k e t .
B e a r i n g
t h e s e
f a c t o r s i n
m i n d
a d e c i s i o n
w a s t a k e n
t o
P e t r o n e l
B i g i o i
i s VP o f
E n g i n e e r i n g
a t F o t o N a t i o n
( I r e l a n d ) L t d . ;
e -
m a i l :
p e t r o n e l A f o t o n a t i o n . c o m .
I l l a r i u R a d u c a n i s a
S e n i o r E n g i n e e r
a t F o t o N a t i o n
( I r e l a n d ) L t d . ; e -
m a i l :
l a l e A f o t o n a t i o n . c o m .
P e t e r
C o r c o r a n i s w i t h t h e
F a c u l t y
o f
E n g i n e e r i n g
a t N a t i o n a l
U n i v e r i s t y
o f
I r e l a n d , G a l w a y ;
e - m a i l :
p e t e r . c o r c o r a n A n u i g a l w a y . i e .
E r a n
S t e i n b e r g
i s C EO
o f F o t o N a t i o n
I n c . ;
e - m a i l :
e r a n s
f o t o n a t i o n .
c o m .
i n v e s t i g a t e
t h e
f e a s i b i l i t y o f
c r e a t i n g
l o w - c o s t
USB
a d a p t e r s
w i t h 8 0 2 . 1 1
c o n n e c t i v i t y
w h i c h c o u l d c o n v e r t
l e g a c y
c a m e r a s a n d p r i n t e r s
i n t o
P T P / I P c o m p a t i b l e
a p p l i a n c e s .
T h i s w o u l d a l l o w e x i s t i n g u s e r s o f PTP
p r o d u c t s
a l o w - c o s t
u p g r a d e t o c o n v e r t t h e s e l e g a c y
a p p l i a n c e s a n d g a i n
t h e b e n e f i t s o f f u l l d e v i c e
c o n n e c t i v i t y
o v e r a h o m e
WLAN
A s
g e n e r i c
l o w c o s t USB
t o
WLAN
a d a p t e r s
a r e
a v a i l a b l e t h e k e y d e s i g n
p r o b l e m s
r e l a t e
t o
t h e
a d d i t i o n a l a d a p t i o n w h i c h i s
r e q u i r e d
t o
t h e
i n t e r n a l
f i r m w a r e
s t a c k s
o f
t h e s e
a d a p t e r s
i n o r d e r t o
s u p p o r t t h e
a d d i t i o n a l
s i g n a l i n g r e q u i r e m e n t s o f P T P / I P
i n
p a r t i c u l a r
t h e
r e q u i r e m e n t s
f o r
d e v i c e d i s c o v e r y
a n d
d e v i c e b o n d i n g
w h i c h
a r e
i n h e r e n t
i n
P T P / I P .
I I S Y S T E M
D E S I G N
A
n u m b e r o f a l t e r n a t i v e WLAN c h i p s e t s a n d
S o C
h a r d w a r e
p l a t f o r m s w e r e i n v e s t i g a t e d . E a c h o f t h e s e
h a d
v a r i o u s
p r o s a n d
c o n s
a n d a b r i e f
s u m m a r y
o f o u r i n i t i a l
f e a s i b i l i t y
s t u d i e s f o r s e v e r a l
s u c h
p l a t f o r m s i s
g i v e n .
I t
w a s
f o u n d
t h a t h a r d w a r e
p l a t f o r m s
w h e r e t h e r e i s
s u p p o r t
f o r
o p e n
s o u r c e
s o f t w a r e t e n d
t o
b e
e a s i e r
t o
w o r k w i t h
a n d
k e y
a d a p t a t i o n s o f
t h e f i r m w a r e
t o
t h e
u n d e r l y i n g
h a r d w a r e
t e n d t o m o r e
e a s i l y
a c h i e v e d . I n i t i a l
p r o t o t y p i n g
w a s
a c h i e v e d
u s i n g
a
c o m m o d i t y
w i r e l e s s
a c c e s s
p o i n t
t o
w h i c h
a
f u l l
o p e n - s o u r c e
o p e r a t i n g
s y s t e m
h a d b e e n
p o r t e d .
T h i s
p r o v i d e d c o m p l e t e
h a r d w a r e
l e v e l a c c e s s
t o a m a s s
m a r k e t
c h i p s e t
f o r
n e g l i g i b l e
s e t - u p
c o s t s
a n d w a s a k e y
f a c t o r
i n
c o m p l e t i n g
t h e i n i t i a l
p r o d u c t
f e a s i b i l i t y
s t u d i e s .
Some f i r m w a r e m o d i f i c a t i o n s w e r e
r e q u i r e d
i n
t h e
a d a p t e r f i r m w a r e
o v e r
a n d a b o v e
t h e
n o r m a l
a d a p t i o n
o f a
USB c o m m u n i c a t i o n s s t a c k
t o
p r o v i d e T C P / I P n e t w o r k
c o n n e c t i v i t y .
T h e s e
i n c l u d e d :
A .
D e v i c e D i s c o v e r y M e c h a n i s m
A
s p e c i a l i z e d
P T P - I P
d i s c o v e r y
p r o t o c o l
w a s
d e v e l o p e d
f o r
t h i s
p u r p o s e
a n d
s e r v e s
a
s i m i l a r
r o l e
t o t h a t o f o t h e r
s e r v i c e
a n d d e v i c e
d i s c o v e r y
p r o t o c o l s :
i t
h e l p s
t o
f i n d
d e v i c e s
a n d s e r v i c e s
i n
t h e
n e t w o r k i n g
e n v i r o n m e n t s . I t s
t a r g e t e d s c o p e , h o w e v e r ,
i s l i m i t e d t o
d i s c o v e r i n g i m a g i n g
d e v i c e s
t h a t
s u p p o r t
P T P - I P .
T h i s
d i s c o v e r y p r o t o c o l
c a n
b e u s e d
i n s t e a d o f s t a n d a r d
p r o t o c o l s
l i k e UPnP a n d
R e n d e z v o u s w h e n t h e
c o m p l e x i t y
o f t h e s t a n d a r d
a p p r o a c h e s
i s
b e y o n d
t h e
c a p a b i l i t i e s
o f
many
i m a g i n g
a p p l i a n c e s .
T h e
p r o t o c o l
i s
b a s e d
o n
UDP
b r o a d c a s t
m e c h a n i s m s
a n d c a n b e
u s e d
i n
c o n j u n c t i o n
w i t h T C P / I P
s t a c k s t h a t
d o n o t
i m p l e m e n t m u l t i c a s t i n g .
B . D e v i c e
B o n d i n g
M e c h a n i s m s
D y n a m i c
B o n d i n g .
t h i s
a p p r o a c h
c a n
b e
i m p l e m e n t e d
o n
d e v i c e s
w i t h
m o r e
s o p h i s t i c a t e d
u s e r
i n t e r f a c e s
a n d
i t
i s
b u i l t
o n t h e f e a t u r e o f P T P - I P
p r o t o c o l
w h e r e t h e
e x c h a n g e
o f GUIDs b e t w e e n d e v i c e s o c c u r s
d u r i n g
t h e
P T P / I P
c o n n e c t i o n
e s t a b l i s h m e n t
p h a s e .
T h e
i m p l e m e n t a t i o n
o f
1 - 4 2 4 4 - 0 7 6 3 - X / 0 7 / 2 0 . 0 0
© 2 0 0 7
IEEE
8/10/2019 04146055
http://slidepdf.com/reader/full/04146055 2/2
P T P / I P i n
t h e
R e s p o n d e r t r a n s p o r t c a n p a s s
t h e GUID
i n f o r m a t i o n t o t h e a p p l i c a t i o n
l e v e l ,
a l l o w i n g t h e
d e v i c e
t o
a s k t h e u s e r f o r p e r m i s s i o n t o c o n n e c t .
S i m i l a r l y , o n
t h e
i n i t i a t o r , a
n e t w o r k c a m e r a s e t u p
a p p l i c a t i o n c a n
a l l o w t h e
u s e r
t o
b r o w s e
t h e
n e t w o r k
f o r
r e s p o n d e r s a n d s e l e c t
o n e .
P T P - I P
P a i r i n g
P r o t o c o l :
t h i s p r o t o c o l h a s b e e n
d e v e l o p e d
s p e c i f i c a l l y
f o r
P T P - I P d e v i c e s t h a t h a v e n o
u s e r
i n t e r f a c e .
T h e
o n l y
r e q u i r e m e n t
i s
f o r
t h o s e
d e v i c e s
t o
h a v e a w a y
t o e n t e r
a
s p e c i a l p a i r i n g s t a t e f o r
a
s h o r t
p e r i o d o f t i m e
( e . g .
a s i m p l e
b u t t o n ) .
T h e m a i n i d e a i s
f o r
t h e u s e r t o
p e r f o r m
a s y n c h r o n o u s a c t i o n
( e . g .
b u t t o n p r e s s )
o n
b o t h
d e v i c e s
t h a t a r e t o e s t a b l i s h a P T P - I P c o n n e c t i o n .
A t t h e e n d o f t h e p a i r i n g i n t e r v a l , b o t h d e v i c e s s h o u l d
h a v e d e t e c t e d e x a c t l y
o n e p e e r
d e v i c e a n d a
p e e r - t o - p e e r
b o n d i s e s t a b l i s h e d .
I I I . P R A C T I C A L
A D A P T E R
E M B O D I M E N T S
A .
PTP
C a m e r a A d a p t e r
T h i s
c a n
b e
e i t h e r
a n
i n t e r n a l o r
a n
e x t e r n a l
PTP USB
t o
P T P / I P d e v i c e
t h a t
n e t w o r k e n a b l e s
a n
e x i s t i n g
USB
d i g i t a l
c a m e r a w h i c h
s u p p o r t s
t h e
PTP
p r o t o c o l .
When
i m p l e m e n t e d e x t e r n a l l y , t h e a d a p t e r t a k e s t h e f o r m o f a
d o n g l e
w h i c h
p l u g s
i n t o t h e
USB
p o r t
o f
t h e c a m e r a . T h e
c a m e r a o n l y
r u n s
PTP
p r o t o c o l
o v e r
U S B ,
w h i l e t h e
PTP
a d a p t e r
a c t i n g
a s e i t h e r a b r i d g e
o r
a
g a t e w a y
r u n s a l l t h e
r e q u i r e d c o m m u n i c a t i o n
p r o t o c o l s
t o
m a k e t h e
c a m e r a
b e h a v e
c o r r e c t l y
a s a
P T P - I P
n e t w o r k
c a m e r a . O n e e n d o f
t h e
a d a p t e r
a c t s a s a U S B - I n i t i a t o r a n d i s c o n n e c t e d t o t h e
c a m e r a ,
a n d a n o t h e r e n d
i s
a
P T P / I P - R e s p o n d e r
a n d
i s
c o n n e c t e d t o a P T P / I P
I n i t i a t o r .
W h e r e
t h e
c a m e r a
i m p l e m e n t s
a
P i c t B r i d g e T M
c l i e n t ,
t h e n a n
a d a p t e r
w h i c h c a n
s u p p o r t
a
s i n g l e
PTP
s e s s i o n i s
a d e q u a t e
a n d a
s i m p l e
PTP
B r i d g e
i s
i m p l e m e n t e d
i n
t h e
a d a p t e r
f i r m w a r e .
T h e
p r o t o c o l
f o r
s e l e c t i n g
t h e PTP
d e v i c e
w i t h w h i c h t h e c a m e r a
c o m m u n i c a t e s
d u r i n g
t h i s
s e s s i o n
i s
i m p l e m e n t e d
w i t h i n a
d e v i c e
d i s c o v e r y
l a y e r
w h i c h i s
r e s p o n s i v e
t o
a
u s e r
a c t u a t i n g
a
p a i r i n g
a c t u a t o r
( n o t
s h o w n ) o n
t h e
a d a p t e r a n d
a n
a s s o c i a t e d p r i n t e r
w i t h i n
t h e
r e q u i r e d
t i m e
o u t
p e r i o d
a n d
w i t h o u t
i n t e r f e r e n c e
f r o m
o t h e r
p a i r i n g
d e v i c e s .
Tr
Prl
I r t
D i g i t a l
C ,
P i c t B r i c
C l i e r
PT P
Respon
USB
S I
D r i v e
p
a m
era
m e r a
I F r
PT P
WLAN
A d a p t e r
J g e
PTP/USB to P T F Y I P
Bridge
it
IPTP USB
PT/I
P
der
I n i t i a t o r Responder
D i D e v i e
~ I
Transport Transport
icvr
ave
USB Host
TCP IPStack
US
Cable
WL NDriver
F i g
1 : P r o t o c o l
S t a c k s
f o r PTP
C a m e r a A d a p t e r
B . PTP P r i n t e r
A d a p t e r
An
i n t e r n a l or e x t e r n a l
P T P / I P
t o
PTP USB
d e v i c e t h a t
n e t w o r k
e n a b l e s
an
e x i s t i n g
USB
P i c t B r i d g e T M
P r i n t e r .
A g a i n ,
when
i m p l e m e n t e d e x t e r n a l l y ,
t h e
a d a p t e r
t a k e s t h e
f o r m o f a
USB
d o n g l e .
Th e
p r i n t e r
runs
P i c t B r i d g e T M
over
U S B ,
w h i l e t h e
PTP
a d a p t e r
r u n n i n g
a s
a
g a t e w a y
r u n s a l l
t h e
r e q u i r e d c o m m u n i c a t i o n
p r o t o c o l s
t o
m a k e t h e p r i n t e r
l o o k
l i k e a n e t w o r k
P i c t B r i d g e T M
p r i n t e r .
I n
t h i s c a s e
o n e ,
e n d
o f
t h e
a d a p t e r
i s a U S B - R e s p o n d e r a n d i s c o n n e c t e d t o
t h e
p r i n t e r ,
a n d
a n o t h e r
e n d
i s
a
P T P / I P - I n i t i a t o r a n d
i s
c o n n e c t e d f o r
e x a m p l e
a c r o s s a V LAN t o a W i F i c a m e r a .
S u c h a t r a n s l a t o r a l l o w s a
c u r r e n t l y
a v a i l a b l e
s t a n d a r d
P i c t B r i d g e T M
p r i n t e r
t o t a l k
w i t h
P T P / I P
c a m e r a s
t h a t
h a v e
r e c e n t l y b e c o m e
a v a i l a b l e
o n t h e m a r k e t .
P i c t B r i d g e I PTPWLAN
P r i n t e r
A d a p t e r [ 7 0 1 a ]
P r i n t e r
P i c t B r i d g e
PTP USB t o P T F Y I P
G a t e w a y
S e r v e r
I
PTP USB
P T P / I P
Dvc
PTP I n i t i a t o r
R e s p o n d e r
I n i t i a t o r
D
e
T r a n s p o r t T r a n s p o r t
D i s c o v e r y
US B
H o s t
U S B S l a v e
TC P / I S t a c k
UB
D r i v e r
C a b l e
lWL N r i v e r
L
F i g
2 :
P r o t o c o l S t a c k s
f o r
PTP
P r i n t e r
A d a p t e r
T h i s p r i n t e r a d a p t e r h a s t w o
i n t e r f a c e s : a W I F I i n t e r f a c e
a n d
a
USB
S l a v e
i n t e r f a c e .
I t s
p r i m a r y
f u n c t i o n i s t o
t r a n s f o r m a s t a n d a r d USB
P i c t B r i d g e T M
p r i n t e r
i n t o a
W I F I
P i c t B r i d g e T M p r i n t e r ,
a v a i l a b l e o n
a w i r e l e s s
l o c a l
a r e a
n e t w o r k . S u c h a n
a d a p t e r p r e f e r a b l y
c o n n e c t s
o n l y
t o
P i c t B r i d g e T M
c l i e n t s
i . e .
P T P /I P R e s p o n d e r s
t h a t a d v e r t i s e
t h e i r
a p p l i c a t i o n
p r o t o c o l
t o
b e
P i c t B r i d g e T ,
i n o t h e r
w o r d s ,
t h e i r i n t e n t t o
p r i n t ) .
I n
p r a c t i c e
t h e a d a p t e r c a n
o n l y b e
i m p l e m e n t e d
w i t h
a
g a t e w a y l a y e r
r a t h e r t h a n
w i t h
m o r e b a s i c
b r i d g e
f u n c t i o n a l i t y .
O n e r e a s o n i s t h a t t h e
l e g a c y p r i n t e r
s i d e
USB
t r a n s p o r t
( u n l i k e
P T P / I P )
d o e s n o t
c a r r y
e n o u g h
s e l f -
d e s c r i p t i v e
i n f o r m a t i o n a b o u t
t h e command
b e i n g
t r a n s p o r t e d ,
s o
i t
d o e s
n o t a l l o w t h e PTP P r i n t e r
A d a p t e r
t o
b e
i m p l e m e n t e d
a s a s i m p l e
PTP
B r i d g e .
R E F E R E N C E S
[ 1 ] I S O
1 5 7 4 0 ,
P i c t u r e t r a n s f e r
p r o t o c o l
( P T P )
f o r
d i g i t a l s t i l l
p h o t o g r a p h y
d e v i c e s , P h o t o g r a p h y
-
E l e c t r o n i c s t i l l
p i c t u r e
i m a g i n g ,
2 0 0 5
[ 2 ] US B I m p l e m e n t e r s
F o r u m ,
U n i v e r s a l S e r i a l
B u s S t i l l I m a g e
C a p t u r e
D e v i c e
D e f i n i t i o n
R e v i s i o n
1 . 0 ,
Odf
J u l y
2 0 0 0 .
[ 3 ]
C a m e r a
I m a g i n g
P r o d u c t s
A s s o c i a t i o n
( C I P A ) ,
P T P - I P
P i c t u r e
T r a n s f e r P r o t o c o l o v e r
I P
v e r s i o n 1 .
0 , J a p a n ,
2 0 0 5 .
[ 4 ]
P .
B i g i o i ,
G .
S u s a n u ,
E .
S t e i n b e r g ,
a n d
P .
C o r c o r a n ,
P T P / I P
-
a
ne w
t r a n s p o r t
s p e c i f i c a t i o n
f o r
w i r e l e s s
p h o t o g r a p h y ,
C o n s u m e r
E l e c t r o n i c s ,
IEEE
T r a n s a c t i o n s ,
v o l .
5 1 , p p . 2 4 0 - 2 4 4 ,
F e b . 2 0 0 5 .
[ 5 ]
P .
B i g i o i ,
E .
S t e i n b e r g ,
G .
S u s a n u ,
a n d A .
P o s o s i o n ,
P i c t u r e
T r a n s f e r
P r o t o c o l
t h e a n s w e r t o
D i g i t a l C a m e r a
C o n n e c t i v i t y ,
P r o c .
o f
t h e
9 t h
I n t l .
C o n f e r e n c e
o n
O p t i m i z a t i o n o f
E l e c t r i c a l
a n d
E l e c t r o n i c
E q u i p m e n t s ,
v o l .
3 , p p .
2 1 7
- 2 2 6 , May
2 0 0 4 .
[ 6 ]
P .
B i g i o i ,
G .
S u s a n u ,
P .
C o r c o r a n ,
a n d
M o c a n u , D i g i t a l
c a m e r a
c o n n e c t i v i t y
s o l u t i o n s
u s i n g
t h e
p i c t u r e
t r a n s f e r
p r o t o c o l ( P T P ) ,
C o n s u m e r
E l e c t r o n i c s ,
IEEE
T r a n s a c t i o n s v o l .
4 8 ,
I s s u e
3 , p p .
4 1 7
4 2 7 , A u g .
2 0 0 2 .
[ 7 ]
P .
B i g i o i ,
P .
C o r c o r a n ,
a n d G .
S u s a n u , D i g i t a l i m a g i n g
s e r v i c e s
u s i n g
PTP
,
C o n s u m e r
E l e c t r o n i c s ,
2 0 0 2 . I C C E .
2 0 0 2
D i g e s t
o f
T e c h n i c a l
P a p e r s ,
p p .
5 4 - 5 5 ,
J u n e 2 0 02 .