Data mode with Sprint PCS and Samsung SCH-8500

Copyright 2000 The Navas GroupSM, All Rights Reserved.
Permission is granted to copy for private non-commercial use only.

Posted as <http://navasgroup.com/tech/sch-8500/>. 

NOTE: This information was compiled by the author and is provided as a public service. The author has no connection to Sprint or Samsung except as a customer. The author is not responsible for any errors or omissions, or for any consequential problems that might result. USE AT YOUR OWN RISK.

Contents

Email comments and suggestions to John Navas.


Getting Started

Picture of SCH-8500 connected to ThinkPad 600The following procedure should enable you to make data connections over Sprint PCS with a Samsung SCH-8500 phone using a Windows 95/98/ME computer (e.g., IBM ThinkPad 600 notebook). The descriptions below assume Windows 98 Second Edition, but the process is similar for Windows 95/ME. (You may also be able to adapt these procedures for other Sprint PCS phones and/or other operating systems.) 

If available, you might want to sign up for the initial free months promotion of Sprint PCS Wireless Web to avoid paying US$0.39/minute for data calls (as of this writing). To further keep costs down you should be able to buy a bare data cable direct from Samsung (888-987-4357) for US$50, rather than pay Sprint US$100 for the Sprint PCS Wireless Web Connection, which is just the cable and some user-friendly software that you don't really need. The Samsung data cable connects easily to a standard notebook computer DB-9 serial port and the SCH-8500 phone.

Start by using the following procedure to create a modem entry for the Samsung SCH-8500:

  1. Start Settings Control Panel Modems.
  2. Add select "Other" (type of modem) Next.
  3. Check "Don't detect my modem, I will select it from a list."
    Don't detect my modem
  4. Next.
  5. Under Manufacturers, select "(Standard Modem Types)."
  6. Under Models, select "Standard 19200 bps Modem."
    (The COM port must be set at 19200 bps or the SCH-8500 will not work.)
    Install New Modem dialog box - Model
  7. Next.
  8. Select your COM port (COM1 in the case of this computer).
    Install New Modem dialog box - COM port
  9. Next Finish.

That installs the modem, and should take you back to Modem Properties, which should be closed with OK, followed by closing the Control Panel.


QNC (Quick Net Connect)

Acknowledgement: Thanks to Bob George for figuring out how to access Sprint PCS QNC!

There are three ways to make a data connection:

To create a DUN (Dial-Up Networking) Connection entry for QNC:

  1. My Computer Dial-Up Networking.
  2. Make New Connection.
  3. Type a name for the new Connection (e.g., "Sprint PCS QNC").
  4. Select device "Standard 19200 bps Modem."
    (No need to Configure -- Windows defaults are fine.)
    Make New Connection dialog box
  5. Next.
  6. Enter no Area code (blank) and "#2932" (including the number sign) as the Telephone number.
    Make New Connection dialog box
  7. Next Finish.
    Finish New Connection

It's important to configure the new Connection. Right-click the new Connection in the DUN window, select Properties, and proceed as follows:

  1. General.
    General dialog box
    Uncheck Use area code and Dialing Properties.
  2. Server Types.
    Server Types dialog box
    1. Make sure that Type of Dial-Up Server is PPP.
    2. Uncheck everything except "Enable software compression" and TCP/IP.
    3. No need to adjust TCP/IP Settings -- Windows defaults are fine.
  3. Click OK to close the new Connection properties.

Using a dial-up ISP

There are three ways to make a data connection:

To create a DUN (Dial-Up Networking) Connection entry for a standard dial-up ISP (e.g., Earthlink):

  1. My Computer Dial-Up Networking.
  2. Make New Connection.
  3. Type a name for the new Connection (e.g., "SCH-8500 to Earthlink").
  4. Select device "Standard 19200 bps Modem."
    (No need to Configure -- Windows defaults are fine.)
    Make New Connection dialog box
  5. Next.
  6. Enter Area code and Telephone number of the dial-up ISP
    (not Sprint PCS).
    Make New Connection dialog box
  7. Next Finish.
    Finish New Connection

It's important to configure the new Connection. Right-click the new Connection in the Dial-Up Networking window, select Properties, and proceed as follows:

  1. Server Types.
    Server Types dialog box
    1. Make sure that Type of Dial-Up Server is PPP.
    2. Uncheck everything except "Enable software compression" and TCP/IP.
    3. If your ISP is one of the small minority that won't work properly with software compression, also uncheck "Enable software compression."
    4. If your ISP requires manual configuration of TCP/IP (most do not), click TCP/IP Settings and enter the necessary information.
  2. Click OK to close the new Connection properties.

Connecting (QNC or ISP)

To make a data connection to QNC or to your ISP:

  1. Connect the cable between the computer serial port and the SCH-8500.
  2. Double-click the new Connection in the Dial-Up Networking window to launch it.
  3. Enter the correct userid and password:
    1. QNC (Sprint PCS):
      • Enter User name "web" and Password "web".
      • Check "Save Password" if you wish.
    2. Dial-up ISP (not Sprint PCS):
      • Enter correct User name and Password for that ISP.
      • Check "Save Password" if you wish.
      • Make sure your location (Dialing from) has the correct area code.
  4. Click Connect.

If everything is set up and working properly, you should first see "Status: Dialing...", then "Status: Verifying user name and password...", followed by a completed connection.

The SCH-8500 enters data mode automatically when it detects the dial out command from your computer. (Manually setting the phone to "Data/Fax In" mode is only necessary on incoming data or fax calls.) When in data mode, the SCH-8500 has an informative display of what's going on, both when dialing, and when connected:

 
   00:00:00   
 Data @ 14.4  
 Rec   Trx    
 999-999-9999 

  duration of connection
  data rate
  receive and transmit indicators
  phone number

Dark blocks appear to the right of "Rec" and "Trx" when the phone is receiving or transmitting data, respectively, much like a regular external modem.

Don't forget to disconnect the Connection (in your computer) when you're done or even when not using it for more than a minute or two so as not to waste air time. (When you disconnect with the computer, the phone should end the data connection automatically, but check to be sure.)
 


Other Dial-up Service

There are three ways to make a data connection:

Sprint PCS can also be used to make data connections to dial-up services other than the Internet; e.g., so-called bulletin board systems. How to do it depends on the particular communications program. Here is a sample connection to the NIST (National Institute of Standards and Technology) Time Service using HyperTerminal Private Edition (free upgrade to HyperTerminal, downloadable from Hilgraeve):

  1. File New Connection.
    Other Dial-up - Name
    Enter desired Name and select desired icon. Click OK.
  2. Enter Area code and Phone Number.

    Select Standard 19200 bps Modem (created in Getting Started). Click OK.
  3. Connect the cable between the computer serial port and the SCH-8500.
  4. To connect, verify correct area code for your location, and Dial.

The SCH-8500 enters data mode automatically when it detects the dial out command from your computer. (Manually setting the phone to "Data/Fax In" mode is only necessary on incoming data or fax calls.) When in data mode, the SCH-8500 has an informative display of what's going on, both when dialing, and when connected:

 
   00:00:00   
 Data @ 14.4  
 Rec   Trx    
 999-999-9999 

  duration of connection
  data rate
  receive and transmit indicators
  phone number

Dark blocks appear to the right of "Rec" and "Trx" when the phone is receiving or transmitting data, respectively, much like a regular external modem.

Don't forget to disconnect the Connection (in your computer) when you're done or even when not using it for more than a minute or two so as not to waste air time. (When you disconnect with the computer, the phone should end the data connection automatically, but check to be sure.)


The Experience

Latency

Latency is pretty bad (even on QNC), many times greater than a dial-up modem connection, and even worse than a geosynchronous satellite link. Here's an example:

 
>tracert www.cisco.com

Tracing route to www.cisco.com [198.133.219.25]
over a maximum of 30 hops:

1  1064 ms   878 ms   899 ms  tnt2.wnck11.pbi.net [206.13.11.10]
2   922 ms   918 ms   999 ms  pop1-e02.wnck11.pbi.net [206.13.11.9]
3  1035 ms   899 ms  1098 ms  core1-a0-0s1.snfc21.pbi.net [206.171.128.177]
4   912 ms   899 ms  1098 ms  edge1-ge1-0.snfc21.pbi.net [209.232.130.20]
5   894 ms   998 ms   919 ms  sfra1sr3-so-1-1-0-0.ca.us.prserv.net [165.87.161.6]
6  1051 ms  1094 ms   899 ms  sfra1br1-ge-1-2-0-0.ca.us.prserv.net [165.87.33.120]
7   928 ms   918 ms   879 ms  165.87.161.201
8   974 ms   899 ms   999 ms  175.at-6-0-0.XR2.SAC1.ALTER.NET [152.63.50.190]
9   904 ms  1058 ms   937 ms  184.ATM7-0.XR2.SJC1.ALTER.NET [152.63.50.82]
10  845 ms   899 ms  2596 ms  192.ATM5-0.GW8.SJC2.ALTER.NET [152.63.49.225]
11  911 ms   999 ms   999 ms  cisco.customer.alter.net [157.130.200.30]
12  887 ms   900 ms   996 ms  192.150.47.2
13  914 ms  1017 ms  1198 ms  www.cisco.com [198.133.219.25]

Trace complete.

Throughput

FTP download throughputThroughput can be erratic and poor (as measured by FTP download tests). Although a 14.4 bps connection should be able to sustain over 1500 cps (characters per second), your speed may fluctuate all over the place, with an average of only about half that (i.e., 750 cps). To the right is a record of a relatively good session (at 9:45 AM).

On the Internet

You should be able to surf the web with your computer, and the phone should maintain the data connection. Large pages will of course load more slowly than a regular modem connection. You can speed page loading by:

  1. Using ad blocking software (e.g., WebWasher).
  2. Turning off the automatic loading of graphics (browser dependent).

You should also be able to use all other Internet protocols; e.g., receiving and sending email at your dial-up ISP, accessing Usenet newsgroups, FTP file transfers, ICQ, etc.

Errors

No protocol errors should be reported in either PPP or modem logs.
 


"56K" Speed

Sprint touts speed "comparable to landline dial-up access of 56.6 kbps" as part of "Sprint PCS Wireless Web for Business" as introduced in August 2000. (See "Sprint Introduces Sprint PCS Wireless Web for Business")

However, this does not appear to really be "comparable to landline dial-up access of 56.6 kbps" as most people would understand it (e.g., a V.90 dial-up modem) -- it appears to be just data compression (e.g., V.42bis) on the existing 14.4 Kbps data service. The key words from Sprint are "up to" -- 56 Kbps could only be achieved with 4:1 compression, which is very rare in practice (outside of synthetic benchmarks). Based on dial-up modem performance data, typical compression will rarely exceed 2:1, for a maximum speed of about 28.8 Kbps.

At best this would bring Sprint PCS up to par with old 14.4 Kbps V.32bis dial-up modems, not current 56K V.90 dial-up modems. In practice Sprint PCS will still probably be much slower than even 14.4 Kbps V.32bis (much less V.90) -- Sprint PCS hasn't been able to stream data at anywhere near its rated speed. (See "The Experience")

To really get respectable data speed, it looks like we'll have to wait for the future.


The Future

Currently the data connection a digital link from your computer over the air to Sprint PCS and then by wired digital network to a Sprint PCS out-dial based on conventional modem technology. The Sprint PCS out-dial modem dials and makes a standard analog modem connection. Data must transit both an air link and an analog modem link in both directions, which is at least part of the reason for the high latency (even on QNC).

PCS data connection

This works, but is clearly a painful kludge. Something better is needed as wireless networks evolve toward higher speeds and IMT-2000/UMTS/3G.


Other Resources


Commands

This section on commands that can be used to control and program the SCH-8500 through the data cable interface was prepared by Mike Milner:

Samsung is not forthcoming with information on the command structure(s) for its CDMA cellphones like the SCH-8500. Unlike GSM cellphones, where commands are specified in a publicly available standard, each CDMA vendor seems to roll its own. As far as I can determine, Samsung uses a subset of V.250 for its AT commands, and a packet-based link-level protocol for low-level access to the memory space of the cellphone. I've found the following AT commands work on my SCH-8500:

Command   Function
ate[0|1]
atm[0-3]
atq[0|1]
atv[0|1]
atx4
at&c1
at&d2
ats7=60
at+cad?
at+cbc?
at+csq?
at+gcap
at+gmi
at+gmm
at+gmr
at+cfc=0
at+crm=0
at+cdv
at+chv
at+crc?
at+gsn
command echo [off|on]
speaker level
return results code [on|off]
display results codes as [codes|words]
enable additional result codes
carrier detect - follow input
enter command mode on CD on off
time out if not connected
service type (analog, CDMA)
battery level
signal level
list capabilities of cellphone
cellphone manufacturer
cellphone model
cellphone firmware version
set Um interface fax compression - none
set Rm interface protocol - asynch fax/da
dial following digits as a voice call
hang up a voice call
extended results codes
appears to be an ESN

So far I've found no AT commands that manipulate the internal phone book or provide access to SMS messages. What little I've seen of the lower level protocol suggests that accessing the phone book and/or SMS is done using the cellphone equivalent of "Peek" and "Poke" commands where knowledge of the internal representation of the data being accessed is in an external application driving the serial link to the cellphone. The cellphone just returns the contents of whatever address is requested - no fancy business that might distract the cellphone from its prime directive. The first binary exchange from the application to the cellphone, after AT commands have identified the cellphone as a SCH-8500, is "7F AA DD 7E", repeated 3 times. Subsequent packets always start with "7F" and end with "7E" - flags that look a bit like a LAPB or LAPD ("7E" on both ends). In the Qualcomm DMSS software description, this service seems to be called SURF-PST and is closely related to CAIT. Lacking a Rosetta Stone, that's all I can figure for now.

Given the cost/performance/power budget the cellphones are designed to, my feelings are that a higher level interface/API isn't likely, whereas the lower level interface potentially exposes too much of the cellphone's internals for comfort, leaving vendors unwilling to share the details a programmer would assume are openly available.

Mike welcomes contributions, particularly any information on reading and writing phone book entries, calendar entries, and/or SMS text. He'd particularly like somebody who recognizes the flag bytes in the binary protocol to point him toward some details in that area.

Additional commands contributed by Eric Sandeen:

Command   Function
AT+IPR=n
AT+GMI
AT+GMM
AT+GMR
AT+GSN
AT#PMODE=n
set serial interface to n bps (where n is a speed returned by "AT+IPR=?")
get manufacturer (e.g., )
get product ID (e.g., SCH8500)
get firmware (e.g., )
get serial number (e.g., )
(0-1) Program Mode? (e.g., 0 off, 1 on)
Program Mode
Command
Function
(must set AT#PMODE=1)
AT#PBOKR=n
AT#PBOKW=n,DATA
AT#PCOUT?
get phone book location (1-229)
set phone book location (1-229); see below for DATA
(0-1) ?

AT#PBOKR Command (must set AT#PMODE=1 to use)
DATA
NAME,RINGERTYPE,ENTRY[,ENTRY...]
NAME
name in double quotes (e.g., "John Doe", "Doe,John")
RINGERTYPE 0-12 (0 Ring 1, 8 Ring 9, 9-12 melodies)

ENTRY LABEL,NUMBER (one to six)
LABEL
1-6 (1 home, 2 work, 3 mobile, 4 pager, 5 fax, 6 no label)
NUMBER (1-32 characters from the set [0123456789*#pT]; first ENTRY sets speed dial)

Example: 5,"Doe,John",3,2,8005551212,1,8885551212
(Location 5, "Doe,John", Ring 4 [3], work number 8005551212 [speed dial], home number 8885551212)

Additional, undocumented commands contributed by Rick Kunz:

Command   Response
AT&F
AT+CAD=?
AT+CAD?
AT+CBC=?
AT+CBC?
AT+CBIP?
AT+CDR=?
AT+CDR?
AT+CDS=?
AT+CDS?
AT+CFC=?
AT+CFC?
AT+CFG?
AT+CMUX=?
AT+CMUX?
AT+CQD?
AT+CRC?
AT+CRM=?
AT+CRM?
AT+CSQ=?
AT+CSQ?
AT+CSS=?
AT+CSS?
AT+CTA=?
AT+CTA?
AT+CXT=?
AT+CXT?
AT+DR?
AT+DS?
AT+EB?
AT+EFCS?
AT+ER?
AT+ES?
AT+ESR?
AT+ETBM?
AT+FBO?
AT+FBU?
AT+FCC=?
AT+FCC?
AT+FCLASS=?
AT+FCQ?
AT+FCR?
AT+FCT?
AT+FEA?
AT+FFC?
AT+FHS?
AT+FIE?
AT+FIS?
AT+FLO=?
AT+FLO?
AT+FLP?
AT+FMS?
AT+FNR?
AT+FNS?
AT+FPA?
AT+FPI?
AT+FPP=?
AT+FPP?
AT+FPR=?
AT+FPR?
AT+FPS?
AT+FPW?
AT+FRY?
AT+FSA?
AT+FSP?
AT+ICF=?
AT+ICF?
AT+IFC=?
AT+IFC?
AT+ILRR=?
AT+ILRR?
AT+IPR=?
AT+IPR?
AT+MA?
AT+MR?
AT+MS?
AT+MV18R?
AT+MV18S?
ATE1
ATZ
OK
+CAD: (0,1)
+CAD: 1
+CBC: (0,2,3),(0-100)
+CBC: 0,100
OK
+CDR: (0)
+CDR: 0
+CDS: (0),(1),(512-65535),(6-250)
+CDS: 0,1,2048,6
+CFC: (0)
+CFC: 0
+CFG: ""
+CMUX: (1,2)
+CMUX: 2
+CQD: 10
+CRC: 0 
+CRM: (0-255)
+CRM: 0 
+CSQ: (0-31,99),(0-7,99)
+CSQ: 31,99 
+CSS: (A,B,Z),(0-16383,99999)
+CSS: B,4186 
+CTA: (0-255)
+CTA: 0 
+CXT: (0,1)
+CXT: 0
+DR: 0
+DS: 3,0,2048,6
+EB: 1,0,30
+EFCS: 1
+ER: 0
+ES: 3,0,2
+ESR: 1
+ETBM: 1,1,20
0
0
(0-1),(0-5),(0-4),(0-2),(0-3),(0-1),(0-1),(0-7)
0,1,0,0,0,0,0,0
0,2.0
1,0
0
1E
0
0,0,0,0
0
0
0,1,0,0,0,0,0,0
(0-2)
2
0
0
0,0,0,0
""
""
""
(0,1)
0
(8)
8
1
""
0
""
0
+ICF: (3),(3)
+ICF: 3,3
+IFC: (0-3),(0-2)
+IFC: 2,2
+ILRR: (0)
+ILRR: 0
+IPR: (0,1200,2400,4800,9600,19200),(38400,57600,115200)
+IPR: 19200
+MA:
+MR: 0
+MS:
+MV18R: 0
+MV18S: 0,0,0
OK
OK

 


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