MarkEagle
VisorCentral Staff

Registered: Dec 1999
Location: Connecticut USA
Posts: 2682 |
Re: How I built a cheap cable to connect a Visor to a Motorola/SprintPCS phone
quote: Originally posted by a3r
Phone TX pin 6 ---> Visor RX pin 1
Phone RX pin 7 <--- Visor TX pin 8
Phone Signal Ground pin 10 --- Visor Ground pin 4
- Pin 1 on the Visor is at the far left (when looking at the visor battery door).
- Pin 1 on the phone is closest to the "End" button.
- All the pins (Visor and Phone) are 0-3v (TTL) not +/-12v RS-232. Neither unit has flow control, but at 14.4Kb max, this should not be an issue.
...
If the assembled cord works correctly, then when the phone and visor are connected together, the phone will "beep" once (the visor must be on for the "beep")
a3r, if you're still lurking out there, can you help shed some light on all this?
I cheated and bought a standard Motorola Data Cable from ePhones. It arrived today. I also made an adapter cable with an ATL HotSync connector on one end and a D9M on the other. It is wired as follows:
HS Conn ---> D9M
1 (RXD) ---> 2 (RXD)
8 (TXD) ---> 3 (TXD)
4 (GND) ---> 5 (GND)
I connect everything up, get the "beep" from the phone, configure my Modem Prefs as a3r outlined above, go to Network, tap Connect, wait..., nothing!!! I get an error that the modem can't be found.
I double- and triple-check everything (hardware and software). It all looks ok... try again... nothing!!! So I whip out my trusty multimeter and start testing the data cable. I find that the only pins that appear to be connected are #10 and #15 on the phone end connected to #5 (GND) on the serial end. I assume at this point that the cable must be defective (even though the charger pass-through seems to work) and call ePhones to get a replacement (very responsive customer service, BTW).
Then I go and connect the cable to my wife's laptop, setup a modem profile and DUN client. Lo and behold, it works!!! I surf the net (on a 14.4 connection) through my StarTAC and SprintPCS!!! The cable is not defective!
So what gives? Here are my conclusions:
1) The StarTAC ST7867W phone must not be using TTL signals (the direct serial connection to the laptop would indicate this).
2) I need a self-powered or Visor-powered serial cable (Mark/Space DataCord?) to connect to the data cable in order to use this configuration.
3) The data cable possibly has a TTL-RS232 converter in it that is powered off the PC serial port (???).
Or am I missing something else here?
a3r, since you don't have your email visible to the forum, could you respond and/or email me at [email protected] with any thoughts you may have about this?
Anyone else that might have any insight, feel free to post it here or send me an email as well.
I thought this would be easy! 
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God bless America, my home sweet home...
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