GI/Jerrold boxes, general info

The information on this page applies to most Jerrold and General Instrument boxes, with some differences between models.

If you have more information on these (e.g. installation/service manuals for the set-top boxes, or details on the meaning of the F key diagnostic functions), please email: philpem@gmail.com

These are accessed by pressing the F key followed by a number key.

Information sources:

• http://web.archive.org/web/20040206170933/chaveiro.catus.net/cable/jerrold_error_codes.html
• http://www.cablechips.users.50megs.com/error.html
• https://forum.nutsvolts.com/viewtopic.php?t=1732
• https://groups.google.com/g/rec.video.cable-tv/c/DpQ411IBro8/m/qtldKj-5-OkJ

+----------+
|  1   2   |
|   -A  -B |
+----------+

This mode permits the monitoring of the descrambler circuit, the FM receiver and the FM signal.

• Digit 1: State of the descrambler
  • C = Clear channel
  • S = Scrambled channel
  • b = Barker channel
  • - = Disconnected
• Digit 2: State of FM Receiver
  • O = FM Data being received “OK”
  • E = FM Data stream error
• Indicator 1: on when the converter sees a purchasable event
• Indicator 2: on when the converter is addressed over the FM data stream

This will show nine digits of serial number information, followed by two digits of firmware version information (on CFT-2100).

• 0n: Place of Manufacture?
  • n=0: Japan
  • n=1: Taiwan
  • n=2: Taiwan (?)
• 1n: Year of manufacture
  • n=last digit of year of manufacture e.g. 1991=1
• 2n: Month of manufacture
  • 20: Jan
  • 21: February
  • 22: March
  • 23: April
  • 24: May
  • 25: June
  • 26: July
  • 27: August
  • 28: September
  • 29: October
  • 2A: November
  • 2B: December
• 4n through 9n: serial number digits (per serial number label)
• 11th and 12th numbers: firmware versions (as per F 3)

The serial number is also on the barcode label on the bottom of the box. Letters are converted to digits as follows:

According to this post by Mixmaster, after the RAM is cleared, the serial number will reset to all 'F'.

Reported as showing the following:

• i: Internal firmware
• r: Expansion ROM version

CFT2100 boxes display the following alternating:

• r0
• h6

• Digit 1: State of FSK data
  • R: receiving data
  • -: idle
  • T: transmitting data (two-way units only)
• Digit 2: Data Parity/Checksum
  • O = Data “OK”
  • E = Data “ERROR”

Alternating display of frequency and level

There are 16 different levels, 0-9, A-F.

Note – both boxes I have display 0 / '83 alternating, for all channels and RF input powers.

Reported in this post by RFslacker to be the return frequency and level the box is set to transmit on, for 2-way boxes only.

Toggles clock on and off

Note – seems to do nothing on CFT2100

• E0: Normal
• E1: Reset timeout, or good FM packet not received
  • If the Timer Mode = ON, then this error indicates the converter has not received a Reset Time-out command.
  • If the Timer Mode = OFF, then this error indicates the converter has not received a good FM packet.
• E2: not used
• E3: not used
• E4: Illegal terminal. The set-top failed the Legal Terminal test.
• E5: Default address. The set-top contains the default address due to a Clear Address command.
• E6: not used
• E7: The set-top has a faulty or wrong (defeat attempt) ROM installed or an incorrect initialization procedure.
• E8: Site code error: The set-top is installed in a system for which it is not initialized (wrong site code).
• E9: Invalid serial number: Bad checksum pattern in non-volatile memory
• EA: The set-top has a faulty RAM or a dead battery.
  • This error occurs if the battery fails to keep the RAM alive during a power down. The error causes the set-top to disconnect and its barker channel to be set at 106.5 MHz.
  • Initialize the set-top to clear the error. If the error persists, the unit is in need of repair.

From http://cd.textfiles.com/group42/HACK/TV/CABLE/CABLE.HTM

 __ __ __ __ - __ __ __
 |  |  |  |    |  |  |
 |  |  |  |    |  |  |___ T = two-way capability, C = PROM programmable
 |  |  |  |    |  |
 |  |  |  |    |  |______ DI = Inband decoder, DO = Outband decoder,  
 |  |  |  |    |          PC = Single pay channel, A = Addressable
 |  |  |  |    |
 |  |  |  |    |_________ Output channel number (3 very common)
 |  |  |  |    
 |  |  |  |______________ D or I = tri-mode system, N = parental lockout   
 |  |  |                    feature (6 dB-only systems are "blank" here)
 |  |  |
 |  |  |_________________ M = mid-band only, X = thru 400 MHz,
 |  |                     Z = thru 450 MHz, BB = baseband
 |  |   
 |  |____________________ S = Set-top, R = Remote
 | 
 |_______________________ D = Digital tuning, J = Analog tuning

• http://systemindustrialgroup.com/Enter/support/CFT2000_DPBB7.pdf – CFT2000/DPBB7 model number decoder and Dynamic Diagnostics
• Time Warner Cable franchise application, May 2003 – includes partial DPBB7300P (Impulse 7000) and ICFT-2000 spec sheets.
  • Identifies the ICFT as the “Intercon” series.
• Time Warner Cable franchise application, Caroline, December 2002 – includes partial CFT-2000 spec sheet.