Telephony binary-coded decimal (TBCD) in Python with Examples

Chances are if you’re reading this, you’re trying to work out what Telephony Binary-Coded Decimal encoding is. I got you. Again I found myself staring at encoding trying to guess how it worked, reading references that looped into other references, in this case I was encoding MSISDN AVPs in Diameter. How to Encode a number … Continue reading Telephony binary-coded decimal (TBCD) in Python with Examples

Open5Gs- Python HSS Interface

Note: NextEPC the Open Source project rebranded as Open5Gs in 2019 due to a naming issue. The remaining software called NextEPC is a branch of an old version of Open5Gs. This post was written before the rebranding. I’ve been working for some time on Private LTE networks, the packet core I’m using is NextEPC, it’s … Continue reading Open5Gs- Python HSS Interface

PyHSS – Python 3GPP LTE Home Subscriber Server

I recently started working on an issue that I’d seen was to do with the HSS response to the MME on an Update Location Answer. I took some Wireshark traces of a connection from the MME to the HSS, and compared that to a trace from a different HSS. (Amarisoft EPC/HSS) The Update Location Answer … Continue reading PyHSS – Python 3GPP LTE Home Subscriber Server

USSD Gateway with Osmocom

Unstructured Supplementary Service Data or “USSD” is the stack used in Cellular Networks to offer interactive text based menus and systems to Subscribers. If you remember topping up your mobile phone credit via a text menu on your flip phone, there’s a good chance that was USSD*. For a period, USSD Services provided Sporting Scores, … Continue reading USSD Gateway with Osmocom